Time for my input (in no particular order):
- Secret of Evermore (SNES): probably the first RPG I ever played...besides Pool of Radiance perhaps...and although it is completely linear I was still able to get completely immersed in the character and what happened to him (and his pooch). A lot more twists, turns and humour than the (very) similar FF series as well, but the biggest plus over FF was by far the music. In SoE the music varied greatly every area, with great environmental sounds as well - the tunes in the FF series used to drive me insane.
- Morrowind: all-round one of my favourite RPG's I've ever played. At the time of its release, the vastness of the land, the graphics and the multitude of quest/storylines really gripped me. Although it is certainly showing its years I still play it regularly and I still enjoy it - the two expansion packs make the whole experience last even longer (if there really is an end of course). The combat system still irrates me sometimes, but it's hardly a reason not to play it.
- Baldur's Gate II: I nearly failed my senior year in highschool because of this game. I've always been a big fan of D&D ever since Advanced D&D was released for PnP roleplaying. Although there was a lot of combat in both games, the gripping storyline and (usually) interesting party members really immersed you into the Forgotten Realms. This was especially true with BGII. Many of the sidequests of BGII were also interesting to do, many of them linked to one of your party members - I distinctly remember the "Tanner/Serial Killer" sidequest in Athkatla. The epic end to BGII was also well done: lost love is always a great motivator for evil!
- Neverwinter Nights: the OC wasn't even much fun the first time round and was plain boring if tried a second time. The gameplay, graphics engine and the toolbox made this my favourite RPG's however. I was part of the Glorwing Persistent World for over two years: intense, roleplay-based interactions; great DM's; good players vs evil players; your actions can affect the history of the world; and I made some lifelong friends at the same time...no other game will ever come close. Many of the SP modules made by the community were also incredible...I think the Dreamcatcher series was one of my favourite.
- Icewind Dale II: Much to my regret I never got around to playing the first game, which I've heard is excellent and probably better than IDII. This game came as a great surprise to me however, as I had already played NWN by the time I got it. Despite it's Baldur's Gate-esque graphics, the story and the music hooked me instantly. I was also thrilled by the idea of playing a drow and seeing the reactions from NPC's towards my character. Tough game to get through from time to time, much more difficult than BG any day, which made it all the more attractive to me.
- Vampire Bloodlines: Finally a game where it is alright to be evil. I'm not one to play evil characters in NWN or BG, but that's mostly because everybody (well, nearly everybody) will react badly towards you. These games almost force you to be good, which to be honest works in my case. I am going to play an evil alignment in my next trip through NWN2 however. Anyway, Vampire is incredibly entertaining and your choices throughout the game have a large impact on the way your character is viewed as well as the ending. The world of darkness has always fascinated me, although I could never get myself into the PnP version, I guess I'm just a closet goth! The graphics are excellent, although while not all features of the engine are used the game often runs a lot slower than Halflife 2 which uses the exact same engine (and uses a lot more effects). The storyline is enough to keep me on the edge of my seat as well, this combined with an excellent soundtrack and very different vampire clans makes this game replayble to me. And let's face it, it feels good to be bad
- Planescape: Torment. If I did make a top 10 this game would most likely be number one. Graphics, music and storyline aside, what counts most for me is how "involved" I can get with my character. For some twisted reason I could relate incredibly well to the Nameless One - probably due to the incredible depth the developers gave to the character rather than my own life experiences. I remember finally reaching the end, and when it was all over I just sat back, not quite comprehending what had just happened. No other game has come close.
That's all the games I can think of right now - the ones I'd want on my list anyway. I've never played the Gothic series (don't hurt me pls) or any of the older DOS games (except Pool of Radiance - was that even DOS?). When I get back to Europe I'll be sure to check these out however as many of you seem to carry these in high esteem.