Dead rising is exclusive to to the 360, well worth a bash.
Definitely this. I loved Dead Rising, and even if you don't want to follow the story, and just want something to do, you can't go wrong with killing a couple hundred zombies in hilarious ways.
The Fable series were my favourites, with Fable 2 being the best IMO (and not available on anything else).
[Edited by Shibby, 11/19/2013 5:07:38 PM]
fable 2 was also the only game of the series that was exclusive to xbox. fable tlc and fable 3 are available on pc