Persona 3 FES (2008)
I described this game
a little earlier in this thread, but suffice it to say that it's one of the most addictive JRPGs I've ever played.
Tales of Vesperia (2008)
Another great JRPG, but this has an active battle system rather than a turn-based one. Great graphics, music, voice acting, story, and good reasons to play through at least a second time... this game is just solid all-around.
Valkyria Chronicles (2008)
A turn-based strategy RPG, it contains a great story, a unique visual style, and unique and compelling gameplay mechanics that have you using "command points" to move your soldiers around the field as you take on an invading army.
Fallout 3 (2008)
Fallout 3 was much like it Bethesda's
Elder Scrolls 4: Oblivion, but was placed in a post-apocalyptic world, which in many ways fit better with the game mechanics. It also contained a lot more humor than
Oblivion.
Burnout: Paradise (2008)
Ulike its predecessors,
Burnout Paradise contained no closed tracks, but simply an entire city in which races had you racing from Point A to Point B, but giving you the freedom to go on any route you chose. Has to be up there for best racer ever.
Borderlands (2009)
A quirky, humor-filled shooter with a
Diablo-like loot system,
Borderlands featured great multiplayer and the constant promise of a better weapon if you just played a few more hours.
Demon's Souls (2009)
The spiritual successor to the
King's Field franchise, Demon's Souls was an insanely difficult yet hugely compelling and atmospheric dungeon-crawler that garnered multiple game-of-the-year awards. Possibly one of the most atmospheric games ever made, and easily in my top 5 favorite games ever.
Mass Effect 2 (2010)
It suffers from "middle installment syndrome" as the second part of a planned trilogy of games, but despite the truncated story,
Mass Effect 2 is about as technically impressive a game as you'll find.
Battlefield: Bad Company 2 (2010)
The first shooter that I've played seriously since
Quake 2. The points system used for online play gives incentives to be more team-oriented, and that enhances the whole experience immeasureably.
Dark Souls (2011)
If this game is half as good as I think it's going to be, it'll probably be my favorite game ever.
I think that about covers it. And yes, I'm including
Dark Souls even though it's not out yet. I'm that confident about it.
If I had to choose just a couple from these... probably
Resident Evil 4,
Demon's Souls,
Mass Effect,
Okami, and
King's Field: The Ancient City would be my top 5.