Not a troll post, I would genuinely like to know. I have purchased the game but have not sat down to explore it yet. Can anyone tell me why this series and why II in particular is so beloved? what about it is so terrific and what makes it a classic? are the BG series based off of the DnD pen and paper games? if so which edition?

Well firstly it's D&D, though there are lots of people who knew nothing about it and still played BG. Yours truly included. It's just another system after all, just one with a lot of fans (of its PnP form that is). Mostly Americans I presume.

Also it was like the first D&D license not to look/feel like a guest from the past on the cusp of the new millenium.

Gameplay wise, it's mostly about a lot of scripting giving you the thrills. Much of which was broken though). Funky characters. Not many that became classics, but still. Minsc and Boo are possibly the most creative... endavour that Bioware has ever accomplished. Party banter, some of it was rather amusing.
In one word, craftmanship. Lots of content too, especially in BG2. It had IMO other downsides though. It upped the game on intra-party interaction however.

And they made it real-time for a reason - the masses don't like TB.

Personally I've never been some sort of a raving fan of the series. Played it quite a bit back then, but given that I barely was in my early teens, I understood little. Always preferred Fallout and some other CRPGs, especially combat-wise. IMO it's the weakest point of all Infinity-powered games.
Along with the low-res prerendered backgrounds (and clunky sprites) which some love. Me - not particularly. Maybe they were aiming for the look of the cardboad PnP decorations? They succeeded then. Sometimes (well, a lot of times actually) you can have a hard time telling whether you walking up, down, over a gorge or through a cave mouth. But people loved it.

Baldur’s Gate has all the trappings of a classical western CRPG and does them all quite well for the most part. A faithful adaptation of the AD&D 2nd edition ruleset ensured a rich character creation and progression system. Combat had a lot of options, a wide selection of monsters and there are tonnes of spells. The story is well-written and there are plenty of areas to explore and the freedom to go mostly go wherever you want. The gameplay flows well and the interface is simple to use and understand. And it has a kick-ass soundtrack.

It’s also a big game you can easily spend more than 70 hours to complete if you have the expansion.

The sequel is essentially the same game with a continued story, except everything is even better. The higher level characters alleviates the worst of the combat-related issues of the first game, the story is grander, every area is meatier in terms of content, dungeon layouts and design is improved, many more of AD&D monster favourites (and some of the most despised!) make an appearance and the NPCs have more personality. And it is simply a massive journey that will stay with you.

Simply put, the games check all the boxes expected from a classical RPG and does pretty much everything either well or really well. Using the AD&D rules and being set in the Forgotten Realms probably drew a lot of attention as well.

Not true. Bigger? Certainly yes. Better? In many regards yes. Amazing journey? Hell no. That was the problem with BG2. Extremely poor main story arch. And I know for sure I'm by far not the only one thinking so. ToB was even worse story- and script-wise. So poorly written that even a certain character that plays seemingly sort of a pivotal (among a couple others) role, not only wasn't supposed to be that important, but wasn't supposed to be in it at all! And was hacked in pretty much on the brink. Tells you all (or much of it) you need to know about the BG2 main quest. I always wondered what's up with this "faithful adaption". Especially when it's not as far as I can judge. Heck, the fact it has RT combat tacked-on (internally it's still turn based ofc) makes it largely... uhmm... unfaithful.
I think the Temple of Elemental Evil was sort of a (much) more geniune attempt to cram a good portion of the ruleset (albeit of 3.5e) into a computer game (and again AFAIU it's still not nearly there). BG is far from it. But again, for me it doesn't matter, cos for whatever reason I played BG it's sure as hell not for the authenticity of AD&D in it. Couldn't care less if it's "right" or not, what I care for is a good game to play.
Combat is hectic. Options are plentiful yeah, but there were many other (and superior IMO) CRPGs in that regard. *only true for BG2. Not true for BG1 even with TotsC though the latter certainly helps. Some of the best quests in BG1 are there too. To each his own, but this is *very* debatable. I kinda like the first one, the second one not so much. Too booming and operatic, just like the main story arch. Or it may be that it's just not nearly enough tracks are there, compared to the whopping gameplay hours BG2 has on offer. It gets very tired.

But I never thought BG1/2 OST to be among the elite. For the reference elite is Diablo 2, PST, Silent Hill 2/3, I'76, Neverhood, HoMM3, Unreal/UT, Anachronox, maybe War/StarCraft, Hitman 1/2. But not BG.

Actually, I think in that it's only turn based in the sense that action games are turn based (they are, it's just that the turns are very fast; Hollow Knight's turns last 1/50th of a second, for example).

What's really going on in the Infinity Englne is something like this:
* Character movements are fully real-time.
* Physical attacks have one set of mechanics. I *think* there's a delay before the character starts acting after being ordered to (affected by weapon speed), then the character attacks at a frequency determined by their "number of attacks per round". I believe moving will re-set this.
* Special actions (including spells, item uses, and special abilities) work on a cooldown system; once a character *starts* a special action, the character can't start any others for the next 6 seconds; if ordered to do so, the character will do nothing until this cooldown expires. Note that this is independent of the physical attack mechanics, so a character can drink a potion (a special action that's instant) then immediately start attacking. (Note that this is not how it works in the tabletop game, where drinking a potion is your action, so you can't attack in the same round.) (Note that you still can't attack before you finish casting a spell, but once you do, you can start attacking again immediately.) I think the BG1/2 soundtracks work well in the context of the game, but don't really work well outside of it. One thing BG1's soundtrack does that I like is that there's a motif that appears in all the battle themes; sadly, this doesn't happen in BG2's soundtrack.

By the way, I'm not actually familiar with any of the games you mentioned, or their soundtracks. For me, my baseline "elite" is something like Dragon Quest and Final Fantasy (and their sequels, and including Final Fantasy Tactics) for classic OSTs, and Hollow Knight and Fell Seal: Arbiter's Mark for more modern ones. (Also Celeste, but that OST is outside of the style I usually go for, or the style of the BG1/2 OSTs.) The progression system isn't really that rich; for many (most?) characters the only choice to make is weapon proficiencies, and I consider weapon proficiencies to be a bad mechanic in games where your proficiency points are limited. (By contrast, they're not so bad n games like Final Fantasy 2, where you can train a new weapon skill up later in the game without any issues.)

mainly because its hard and tactics actually matter

True. Forgot to mention it myself.
Fallout, Diablo, Jagged Alliance, Wizardry 8, even Anachronox (and many others) have way richer, fiddlier systems.
But the DnD ppl obviously don't care. The 3/3.5e makes things a tad more interesting. I only play PC.
However the Diablo 2 and Unreal/UT ones are like industry standards. Also, SH2/3 composer I think still tours on the back of the PR he got with those OSTs. He was even in my neck of the woods. I was referring to the combat system only.
Anyway the Temple of Elemental Evil engine wipes the floor with Infinity in every possible measurement. Hard only the first time around. Or if you 11-13 yo like I was back when BG1/2 came out. Nevermind both...
Or if you're just outright stupid and only whine about games being hard)

Most of the tactics in BG1 is knowing the ways and quirks of the game. Thus the second time you play it's a breeze. TotSC try to change that a bit.
BG2 requires more effort.

But eg JA2, Wizardry 8 or Diablo 2 all have more to offer in both regards (diff-y and tactics).

Character movement is something that happens during battle, and it can easily influence the outcome of a battle. It still doesn't solve all the issues with the game, and it creates the problem of having more irreversible choices to make at level up time. Also, dual casters are worthless in 3.x without taking advantage of certain additions to patch over that flaw (note that Mystic Theurge is not in 3.0 core (it is in 3.5 core), and I am not aware of any D&D-based CRPG that implements that class). Thing is, I like playing dual casters or Final Fantasy style Red Mages (similar to D&D 2e's Fighter/Mage/Cleric) when they're viable (like in FF1 and FF3 remake (but not original FF3 once you reach the mid-game)), and in 3e, they're not.

Another issue is how long it takes to see any character growth at all. Final Fantasy games (except 1, and excluding 2 due to its level-less system) have far more frequent level ups, and Wizardry 8 allows for skill growth between level ups (not to mention that the first couple of level ups come quickly, unlike in BG1).

It provides an escape from the miserable existences of our lives.

BG2 is particularly good because:

The writing actually sounds like someone put thought into it before typing it into the game.
The combat is as complex as you want it to be, there's literally hundreds of spells.
Tons of classes and items that provide different ways to build a character and something to look forward to during progression.
Surprises, easter eggs, and hidden secrets are plentiful to happen across regularly.
It's a massive game with content that took me well over 100 hours to explore everything my first playthrough.

Basically, it's one of those game you play and start to remember that they just don't make games like this anymore. It's something people made with care for people who like RPGs to truly enjoy. The game is artisanal. And it works on every level. Story, combat, everything.

BG1 was better on exploration (you could just wander openly outside, tons of buildings in the city), but BG2 outshone it in every other respect. BG1 was still a great RPG, with well done story and writing, but the combat and character building/progression wasn't as exciting due to the low level cap and less class options.

They're just some of the best RPGs ever made. BG2 is essentially the gold standard by which western RPGs have been judged ever since. Only Witcher 3, 15 years later, seems to come close to its level of reverence in the hearts of PC RPG gamers.

Pathfinder: Kingmaker has Mystic Theurge.

This superbly summates my opinion. Also just wanted to add that growing up during the period when these games were the norm also adds significantly to the experience. Plus the fact that it trounces modern day giants like Skyrim also gives it a sort of added significance as well. Though with recent games like Witcher III and Red Dead II I'm glad to see these traits resurfacing somewhat.

I agree. It's one of my top five games ever, for the reasons mentioned. It wouldn't be if it were released today, and I can understand why it may not seem like a big deal for people who have encountered it only in recent years. But at the time, it was one of the best we had ever seen in its category. It came from the same Black Isle Studios lineage as the original Fallout and Fallout 2, Icewind Dale, and Planetscape Torment, all of which have legendary RPG status.

SORRY, I try to translate it later in englisch. :-)

10 Jahre vor BG, brachte SSI Pool of Radiance auf dem Markt, mit 3 Nachfolgern:
Curse of the Azure Bonds, Secret of the Silverblades, Pool of Darkness

Dazu noch ziemlich gut: Champions of Krynn, Dark Knight of Krynn und Dark Queen of Krynn.

Für mich sind PoR und PoD absolute Klassiker, ebenfalls die Krynn-Spiele. Schon 10 Jahre später wirken diese gegenüber winzig. PoD und DQK waren riesig. Und PoR war schon ähnlich frei wie BG in der Entscheidung was man macht. Neverwinter Nights 1 hatte ich links liegen lassen und damit ein Pool of Radiance Mod gespielt.

Gerade PoR und der 4. Teil PoD und die ganzen Krynn-Spiele CoK, DKK, DQK waren es Spitzenspiele der Zeit.

So sahen aber diese 9-11 Jahre später mit Fallout, BG und Planescape: Torment einfach nur blass aus. Mehr Story, Spieltiefe, fanstastische Charaktere, eine offene Welt, Wiederspielbarkeit und dann noch eine Modderszene die 20 Jahre lang Mods schrieb. Während die alten oben genannten AD&D 1st Edition Spiele nur Teile der Regeln und Zauber nutzen, waren bei BG fast alles von der AD&D 2nd Ed. integriert. Und waren auch sehr dicht an dem Regelwerk.

Planescape: Torment ist für mich immer noch Top 1 in Spieltiefe und Story. BGT und Fallout 1-2 gehören für mich immer noch zu meinen beliebtesten Spielen. Die ich gerne wieder rauskram, schaue ob ich es modden kann und ab die Post.

you can't meaningfully play Fallout/BG/PST being 10 yo. I know, I've tried. Also, BG characters are way less fantastische than those of the other two.