RPGs released in 2008:
I'll reserve my judgement until I finish Storm of Zehir and play some other games I intend to play.
Best RPGs of all time:
1. Planescape: Torment
Superb story, NPCs, character interaction, dialogues and atmosphere. The game itself is a huge character generator, building (or rather, discovering) your character both literally and figuratively. It is great example of integrating the story and the game mechanics (gaining experience = remembering). Planescape: Torment was a game that made me care about the characters. In one moment you are laughing at Morte's jokes and in another moment you're contemplating the meaning of life and the planes. Game world and characters really became alive in PS:T.
2. Fallout
If I wanted to define a computer role-playing game in one word, I would say Fallout. All essential RPG elements are implemented in this game, and they are implemented very well. For me, Fallout is a standard according to which I measure other computer RPGs. Unfortunately, almost no game has reached that standard. A game with Fallout's design elements with additional depth in story, dialogues and character interaction (e.g. like in MOTB) is something that game developers should strive to achieve. I think that I'm going to replay it as soon as I finish SoZ.
3. Fallout 2
Fallout 2 expands on Fallout's design, with the same strong points like the character / skill system implementation, combat, quest design and character interaction, adds a small but significant interface improvement (pushing the characters out of the way), there is significant additional content - there are more areas to explore and problems to solve than in Fallout. However, Fallout 2 has deviated from the setting more than a bit (e.g. New reno, which is incidentally the best part of the game), making the game rather inconsistent compared to Fallout. Also, the Enclave / the President / Frank Horrigan can't compare to the Master. With all its shortcomings, only two games better than Fallout 2 have been made so far.
Nearly made the cut (in no particular order):
Arcanum - it has almost all strong points of Fallout, except for combat, which was horrible enough to keep it out of top 3.
Neverwinter Nights 2: Mask of the Betrayer - Story, dialogues, characters and their interaction are not quite as good as in PS:T, but are the next best thing. I loved the Spirit Eater feature and how that essential story element was implemented in game mechanics. Choices and consequences are there as well and the Influence system is a great feature, which needs further improvement (it has been improved with respect to KOTOR 2). However, NWN 2 combat leaves a lot to be desired and thanks to it MOTB stays out of top 3.
Honorable mention: KOTOR 2 (with TSLRP), Vampire: Bloodlines, Baldur's Gate 2, Ultima 7