I was going to ask which class is best for a first time play-through, but there are a couple threads from 2012 that ask the same question and I'm not sure what the GOG necro policies are. I'm going to try and ask more than "best class?" so this isn't the exact same as those topics.

My most significant question is what class you all think would be best for me on my first run of the series. I'm not sure how relevant this info is, but I burned through the Souls games for their platinum's recently, and have been investing a significant amount of time into The 7th Saga and Shin Megami Tensei IV. I've been avoiding magic as much as I can all three games, so I'm up for a nice change of pace by playing a magic-based character.
Short: What's the best class for a first-time run and why?

My other question is about staying interested in the game. Are there any exceptionally uninteresting areas of the series that I should be prepared to slog through? And if so, how did you get through them?

Aside from those questions, I'm happy to hear any advice or info you all have to offer about what I should or shouldn't do on this first run, and anything else in the series that you think is worth mentioning.

I haven't spent much time playing as an archer in any games, outside of Dragon Age; Origins and Dragon Age II.
Is it a fun play-style for BG 1?

Okay, a standard mage sounds like it will give me a lot of variety, which is what I'd hope for if I'm playing a mage.

I absolutely love playing as a cleric/healer! Would Icewind Dale be a good series to play after Baldur's Gate, or is it too much of the same thing to the point of burn out?

I actually wouldn't recommend mages in either game. They are a little complicated for a beginner even though they excel in BG2.

What class would you recommend I play in BG 2?

I'd recommend fighters. They are pretty tough and they are the most versatile when it comes to equipment like weapons and armour.

Edit: Also, you'll need at least one thief to find/disarm traps and pick locks. That is the one thing in Baldur's Gate you can't do without. In both games you get a pretty good thief (Imoen). Be careful with your spells and wands. A lot of them have an area of effect, and if a bystander just happens to get in the way you'll be hunted by the law. In BG1, you'd want to have a person with high charisma leading the party. If that person is someone fragile, like a mage, make the switch before and after completing quests. That's all I can think of for now. I'd also recommend using websites if you need help with anything. Here's a few:

Gamebanshee
Mikesrpgcenter
Sorcerer's Place
Forgottenwars (AKA Dudleyville)

So I should run a high-charisma archer (fighter with bows) through both games? Keeping a thief on my team doesn't sound too hard, I remember doing that for nearly all of my DA;O and DA2 play-throughs.
And thank you for those website references, they're extremely helpful!

If you have Imoen in your team charisma is irrelevant, since she has high enough CHA to be your front man in any situation. The most important being shopping. Note that the game only factors the lead character's charisma, so even if Imoen is in your party, and you send her to shop, if she is not in first position her charisma will mean nothing. She *must* be placed in first position before speaking to other npcs or shops.

So I shouldn't invest any CHA in my main character? I don't mind save-scumming if it's a matter of always keeping Imoen in front of my party for conversations and shopping, or would that cheapen the game too much?

Don't take other people's word as some sort of bible formula. Play the game how you see fit. Take advice, by all means, but use that advice only to tailor the game to the way *you* want to play, otherwise you may as well just watch let's plays. Give your character stats that fit his/her class, background, etc., unless you intend to merely power play, in which case just min/max everything.

Playing a cleric is no bad choice for the BG series. You get quite some HP, can wear the heaviest armor and get bonus spells for high wisdom. Neither in BG1 nor in BG2 is a good aligned pure class cleric NPC.

Clerics don't get even close to fighters with composite bow in terms of dealing damage and but if you don't insist on being the one with the most kill percentage in the party it's a good class to play and fulfill the healer and summoner role in the party.

Also, if you have 18 strength, Draw Upon Holy Might can raise that to 19 (at character level 3), which is a huge bonus.

In BG2, there's Holy Power and Righteous Magic as well.

Edit: Or, in BG2, I think you can play a Half-Orc Cleric and *start* with 19 Strength.

Okay; that's good advice I'm going to remember, thank you very much. I've had that issue with some longer RPG's where I've followed other people's advice to the letter, and it ended up really detracting from my overall experiences.

Playing a Cleric sounds like something I would be more comfortable with for a first-run, because it's a role I'm familiar with across RPG's. Any advice for a Cleric play-style that I should keep in mind?

Healing magic is weak in these games. Healing during battle is usually not the best strategy.

Don't underestimate the value of support spells.

Spiritual Hammer is not useful in the Baldur's Gate series. It is decent in Icewind Dale (where it gives you a long range melee attack) and in Dungeon Hack (where it acts a thrown weapon that returns to you, possibly hitting enemies it originally missed).

Are there (m)any good Support-spell Cleric builds?