Well, when you wish to go back into it, here are some tips for the future:
Dragon Age Origins

That website is great for any game you plan on playing.

EDIT: Hyperlinking is giving me trouble for no apparent reason right now !

Planescape: Torment

Fallout 1+2

UnderRail

I vouch for any of the three Dungeon Siege games. DS 2's expansion requires a simple registry hack to get running in Win 7/10, though, so be aware of that if you want the "complete" experience. Dungeon Siege 1 and 2 also have systems which grow your character based on the skills you use, similar to Everquest's systems from back in the day, I'm told.

Hey, thanks for the site recommendation, didn't know about it. (+1)

It's because of the colon (:). You need to replace it with %3A

Dragon Age: Origins

Edit:
For ARPGs I recommend Nox and Torchlight series.

Age of Decadence is pretty great because it has meaningful choices and a good combat system. If you had something like that with a more epic story, a party with meaningful interactions, higher production values and a less cynical setting, you'd probably have the perfect rpg.
But all the crpgs I've played so far have some serious flaws (e.g. Fallout 1&2 have crappy, simplistic combat, Baldur's Gate 1 has too many boring fetch quests, Baldur's Gate 2 is too restrictive in how you can solve quests, Kotor 1&2 have horrible combat that is repetitive and mostly unchallenging etc.).
I'll probably try Dragon Age again some day, the party interactions are supposed to be nice iirc.

FPS-RPGs
Deus Ex and Human Revolution
System Shock series
Borderlands series

Isometric RPGs
Grim Dawn
Heretic Kingdoms series
Torchlight series

When I started reading your post and saw the words "old computer", I actually first thought of a computer that would be too old to run those games. I was thinking along the lines of Apple 2 and Commodore 64, where you would be looking at games like Wizardry 1 and Ultima 4/5.

Ah, I see. What you want is more of an interactive environment where the worlds evolves around you. Most of the games mentioned here are stories which you work through stage by stage. So pretty different in scope. I haven't play age of decadence yet, nor actually played anything where the "choices" are meaningful in any way. Not sure your going to find and epic story and meaningful choices in one game, it would mean writing the story in hundreds of different ways.
Borderlands is just a fps.
Grim dawn, and torchlight are action rpgs.

Only briefly scanned your list but I didn't see Shadorwun. Shadowrun Dragonfall and Hong Kong are great games, and should run on an older PC.

Divine Divinity

My favorite. :)

Nice, fixed it now.

Thank you.

It's FP-RPGs. The 'S' stands for 'Shooter'.

I finished the retail version months ago, since the Steam version is missing the expansion pack.

It was kinda ok and easy to play, but I have to admit it was very repetitive at times and even boring. Not much really changed throughout the whole game. Even though you got a bit better equipment all the time and faced increasingly more powerful enemies, it just felt exactly the same throughout the game. I couldn't even tell by their looks that the monsters near the end of the game were somehow more dangerous than some early monsters in the game, even though they were.

Even the locations seemed pretty much the same. Sometimes you were in a forest, then some desert, then some jungle, then some tundra, then some snowy hills, then some beach, then some forest which looked exactly like the earlier forest, repeat... There weren't really places which stuck into your mind, it was all generic.

Also one thing I didn't like about the game, just too much loot. It is as if each and every killed enemy dropped like 5 items or more, and after every battle you'd go through 50 items lying around, which to take, which to keep, which to turn into gold in that spot with a specific spell, etc. I presume the excessive amount of loot added to the game was due to the multiplayer?

I feel the best thing about the game was that the user interface and gameplay system to me felt very well thought out, taking out or automatizing things that made sense. So in that sense it was a joy to play. Like that "turn item into a money (or a potion)"-spell that I mentioned above, it was a good addition to the game as it lessened the need to constantly run to town stores in order to sell excessive loot (which you would still be doing a lot).

Yes, sometimes the game is like a "bag simulator" to keep the more valuables items: drop & grab. I travel with two donkeys equipped to full (potion and shields,swords,etc). When you found a merchant the game begin... Like you say, some process could be more automatics. But is a game from 2002, is very addictive, excellent OST and very cheap.