Never saw this game before. Looks like old school awesomesauce!
Can't forget Zork...you have been eaten by a grue...good stuff!
Hard to pick one, so here's a few.
WoW. Had to quit playing as it was wrecking my life. That's a fun game.
Alternate Reality (The City and The Dungeon) on the Atari 8 bit and C=64. (IBM/Amiga/Atari 16 bit, but I only played on the former) Amazing detail in a game from mid 80s! They dabbled in making an update in the mid to late 90s, but it's fizzled.
BG2 and PS:T. Legendary games. If you haven't played these, they both hold up very well. BG2 was one of the last games that was HARD! I don't mind the sissification of today's games, as I don't have the spare time I used to, but you rarely get a sense of accomplishment after a tough battle nowadays.
Ultima 3. Another amazing game ahead of it's time.
Oblivion and Fallout 3/NV. Many people crap on these, but when you can make a game where you want to ignore the quests and explore, it's a great game.
Gothic 1/2. Not perfect, but you were always rewarded for exploring, and that made it fun!
Black Isle in general. Fallout 1/2 also legendary. I've loved every Black Isle RPG.
Not enough Baldur's Gate 2 love in here. If you have lots of time, Baldur's Gate Trilogy is REALLY the way to go (meshes BG1 and BG2 together using the BG2 engine). Epic storyline, tons of characters, so much dialogue and so much to do. It aged relatively well too since it's sprite-based. There are lots of mods that can add variety to the game. Unfortunately for me I think I've played through the game one too many times (I think I've done at least 10 playthroughs) so I know where everything is and have talked to just about everyone.
No offense, but how many hours did that take??
Overall Baldurs Gate 2. And if you put them all together its the Baldurs Gate Saga, which gets better as it goes on.
Most of the other named titles here are also excellent. I would have picked the KOTOR saga except we got a rushed, half-assed sequel and no finish to the trilogy.
Had they done it right that would easily have been the best RPG ever.
I really wish games like Planescape Torment would be redone with the Dragon Age 2 engine. But I guess those type of games wouldn't sell well anymore.
Can't forget Zork...you have been eaten by a grue...good stuff!
Planescape Torment > *