Xbox 360:
Call of Duty 2 Mostly for achivements.
Rumble Roses XX Bought it when I got my 360, played 4 hours of it.
Grand Theft Auto:The Trilogy Pack I've beat all GTA's on PS2 and started San Andreas again and got 14 hours into it.
Dead or Alive xtreme 2 The amount of time you have to put into it is insane to get any type of achivements.
Halo 3 I did alot of the game and beat it in coop but never single player. never even went online (Like Gears of War).
Xbox 360 Live Arcade:
Gauntlet Played 1 hour and left it lol.
Castlevania:SOTN I played it for 10min LOL! 
PSP:
I've come across alot of games /cough and my list of games is building up. I'm playing almost 5 different ones at a give time with a backlog now and it's going to get worse.
Lucky I've stopped buying Xbox 360 games since about November due to funds and not alot of time. Once I get some cash going I'll be buying all the ones I've missed. Mass Effect, COD4, PGR4, Orange Box....ect. The cool thing is I got the Special Edition of GTA4 already pre-ordered and paid for so it's no prob lol.