If you dont mind older games then here's a few suggestions, all absolute classics, yet none of these games are so old that they're hard to tolerate/outdated, hard to get into nor really demanding&hard. I wont burden you by including too many games, but here's a few of the best PC games of all time.
Planescape: Torment (1999): Largely considered to be the RPG with the best writing/dialogue/story of all time. It's one of a kind with a very intresting world and characters but a combat system that is quite boring and visuals that aren't all that great. On top of that you spend most of the time talking to people, I guess it depends on you whether that's a bad or good thing.
In order to enjoy this game you need to be able to tolerate a slower gameplay pace and the fact that you'll be reading
a lot of text. But it's like reading a good book, once you start to make progress the story just captivates you, and my what a story it is. It's easily the most "intellectually engaging" game I've ever played, not because the gameplay is very strategic, but because of the amount of intresting dialogue in this game. Some people have said that this game is kind of like a WRPG and JRPG hybrid and I can see where they're coming from. I guess this game doesn't sound all that exiting before you play it, but belive me it's worth all the hype it gets. To me this game is like Persona 4 (captivating storyline, awesome characters) with a much more unique and intresting setting and a lot more "deep"&philosophical writing. Persona 4 itself is already one my favorite RPGs of all time so that should say something about the quality of this game...
Gameplay video. Not very representative of the game as a whole mind you, but it gives you a some kind of picture what the combat's like.
The Curse of Monkey Island (1997): Third game in the legendary Monkey Island-series. While games 1&2 are the true classics, the third game has
awesome cartoony graphics that are just beautiful to look at and the gameplay was simplified from the first two games. It's a comedic point and click adventure game with good voice acting and memorable and really funny writing. I'd say that this is probably the best way to get into the genre, it's just so easy to get into this game and start playing it. Just and all around a very pleasant and positive gameplay experience imo.
Gameplay video
System Shock 2 (1999):
While the original System Shock is the true innovator, it's quite complicated and hard to get into compared to the second game, which is easily one of the best FPS games of all time. The System Shock series pioneered the FPS/RPG genre and the games have a very large influence on the FPS genre. Bioshock is basically System Shock 2 lite, not nearly as good as SS2 though. It has an amazing storyline for a FPS game, really awesome athmosphere and it's a great and very well executed mix of RPG, horror and FPS. One of the scariest games I've played despite the poorly aged graphics, all thanks to excellent voice acting and soundtrack.
Gameplay video
Thief II: The Metal Age (2000):
You probably already read about this game on the stealth game thread so I'll just say that this game is considered by many to be the best stealth game of all time. Stealth gameplay done right (getting caught isn't an instant game over, unlinear sprawling maps and multiple ways to solve problems etc), a strong athmosphere, a very intresting gameworld and a plot that is quite intresting.
The first game, Thief the Dark project (Thief 1) is more combat oriented and has less refined gameplay but a more supernatural and intresting levels and plot.
Gameplay video
Deus Ex (2000):
This game is a mix of Thief, System Shock and Half Life and it has a very strong fanbase of people who think that it's the best game of all time. Just like the System Shock games, this game has an absolutely amazing plot for a FPS game and it has some of the best (and most philosophical) writing you'll ever see in a video game.
Gameplay video
UFO: Enemy Unknown (1994):
Another one of those "many people think it's the best game in it's genre" type of games. It's an addictive strategy/turn-based tactics game with an alien invasion theme, if you've played the new X-COM on PS3/Xbox 360 you'll have a pretty good picture of what this game is like.
Gameplay video
Baldur's Gate 2 (2000) and
Fallout 2 (1998). Usually when talking about PC or WRPGs, these are two games that are tied on the number one spot. They're the PC equivalent of Final Fantasy 6 and Chrono Trigger on the SNES (while Planescape: Torment is kind of like Earthbound in the way how it breaks many RPG conventions).
Ultima VII (1992) is another strong contender but it's harder to get into than these two games.
If you like Half-Life 2, then
Half-Life(1998) is definitely worth a playthrough. And if you haven't played Half-Life 2, definitely check it out (and don't forget
Portal while you're at it, if you haven't played that one yet). Although I guess you can play HL2 and Portal on consoles.
