Red Dead Redemption
Little Big Planet
Bad Company 2
haven't played arkham city, sonic generations, and unfinished swan,
but my opinions on the rest are:
Brotherhood: best of the ezio trilogy imo
Red Dead Redemption: good story, good gameplay, although the wilderness is a little empty (unsurprisingly)
Little Big Planet: played it on the psp, didn't finish it
Bad Company 2: other than the 'traditional fps' aspect of it, the destructable environment is pretty cool, and the story is also pretty cool...
If you want games that'll last you a while Batman Arkham City and Little Big Planet would be my choices, or the other ones if they're long except of course Sonic Generations you could finish that game in a day if you want to unless you go out of your way to do all the challenges.
I've played all of them. Red Dead will last you the longest. Arkham City was pretty good too. Brotherhood just felt like 2, but it was decent.
Fresh to death
prince of Persia moveset: http://community.us.playstation.com/t5/PlayStation-All-Stars-Battle/Prince-of-Persia-in-all-stars/m-p/38273897#M125640