Let's see:
Planescape: Torment - Played and completed once. I don't feel a strong urge to replay it due to the fact I got the 'optimal' experience the first time around by making a character with high wisdom, intelligence and charisma. Planescape is still one of my favorite RPG's of all time, make no mistake. I just happen to have this thing where, sometimes upon playing a really good game or watching a good movie, I don't feel like returning to it again. I like to just let the experience fester in my brain.
Fallout: A Nuclear Roleplaying Game - I've played Fallout quite a bit. It's my favorite of the bunch. A very pure experience compared to the later installments
Fallout 2 - Same as above. Fallout 2 is not as good as its prequel, but I've probably played it just as much.
Baldur's Gate II: Shadows of Amn - I've poured I don't know how many hours into BG2. As a kid, this game was
everything I wanted in a video game. I must have completed it at least 5 times during my childhood, each time with a chaotic good sorcerer and the same party setup.
Arcanum: Of Steamworks and Magic Obscura - I never completed Arcanum, but I did play it for a bit back in the day. The game got worse as it progressed and I lost interest, but the first three quarters or so were very good, as far as I remember.
Vampire: The Masquerade - Bloodlines - Steam says 192 hours. I honestly don't know how I managed this. This game is excellent, but this is borderline obsessive. Something about the atmosphere (and loneliness, I suppose) made me return to Bloodlines again and again, even if I knew absolutely everything about the game after the first three or four runs. Fun fact: I never in my 200 hours played as a nosferatu.
The Elder Scrolls III: Morrowind - I've played this, but never completed it. I get why this game is good, but I just kept reaching a point where boredom set in. This actually happens in most open world games I play, including New Vegas. There's something about them that promise so much, but many of them inevitably end up becoming repetitive.
Fallout: New Vegas - I'm so close to completing New Vegas. I'm probably at the point right before deciding who to side with. Steam says I've put about 100 hours into it, but it's because I keep starting over. Like I said, open world games are more fun in the beginning, where everything is unexplored and mysterious. NV is still an excellent game, though. If you take into account I almost
never complete sandbox RPG's, getting as far as I got speaks to its quality.
Gothic II - I remember being so, so very excited when I bought this as a child. The first Gothic was really good, but when I played the G2 demo I was hooked. The various ways the game let you access the main city was a strange sort of highlight for me. It was because of the agency given to the player, which I absolutely dug. I joined the rebel faction because they were the coolest, although I do think I had a subsequent run as a mage. Gothic 2 was awesome, but guess what: I didn't finish that either. It got more and more linear, which turned me off. I disliked how the different paths would converge towards the end, although this was worse in G1.
Wizardry 8 - I never played Wizardry 8. I just sort of missed it.
Deus Ex - Is this the greatest game ever? Maybe. And I'm not even being nostalgic, because I don't think I played DX until I was in my early-mid twenties, at which it had been out for at least ten years. I wanted this game so badly as a kid, but never got it. I think I played the Invisible War demo which wasn't too impressive.
Neverwinter Nights 2: Mask of the Betrayer - This is one of my favorite games on this list. A modern (maybe not so much anymore) Planescape and all that. The fact there are so few recruitable characters is a good thing, as they all get to play a large role in the main narrative.
This is how you write party members. They fit into the setting and have a reason for joining you. I'm still amazed at how much freedom this game gives the player. Doing things out of sequence, skipping entire sections of the game, going for some deliciously evil options... At the time I when MoTB came out, I had resigned myself to the fact that all RPG's offered cosmetic choices at best, but then I was proven wrong.
Jagged Alliance 2 - I never played this. Sorry guuiiiiizzzz.
Dark Souls - Yeah, I put a few hours into this. On PC. The controls were so lackluster I couldn't go on playing it. I have limits. Also, the game deleted my saves, for some reason. If one day someone decides to make a port that's actually good I might pick it up, but my tolerance for poor interfaces and shitty controls is low.
Wizardry VII: Crusaders of the Dark Savant - Never played this.
Betrayal at Krondor - Sorry.
Baldur's Gate - This was my first RPG. I had the version with 6 different CD's. I liked this game a lot as a kid, but maybe more for what it promised than for what it delivered. The second game is where it's all at.
Darklands - Nope.
Star Wars: Knights of the Old Republic II - The Sith Lords - Yup. I was obsessed with Kotor 2 back in the days. I also loved the first one, which I don't know if I still would today. This is a very good game. I found a really good LP where the author went through everything that was cut. I think it's stored on the LP archive.
Ultima Underworld - Didn't play.