JGR/JSR, etc...
I loved Jet Grind Radio (or Jet Set Radio, as I played it) ;-) I love JSRF too, but not as much as the first - maybe it's just that it wasn't a brand new concept the second time around.
Also, Power Stone, for the DC and Power Stone 2 - those games rule.
The Buffy games on the Xbox I also liked - the graphics are horribly, but they have fairly solid gameplay, and are fun. (of course maybe being a Buffy fanatic influenced my opinion on these ones).
Also, Illbleed was very very weird, but strangely addictive. Though not without problems, I really enjoyed this game and had to finish it.