I dunno how much you like multiplayer in general, but I would be iffy about buying Uncharted at retail price if you don't. The campaign mode is freakin' amazing, but it's only 10 hours of amazing. Best rental ever, though.
Star Wars TFU is basically an action platformer, and very enjoyable, but even shorter than Uncharted.
If you like the first 3 Metal Gear games, MGS4 is fucking incredible. If you don't, or just don't like long cutscenes, you will despise that game. Personally, I love MGS, but the long cutscenes began really grating on me in MGS4, especially since MGS3 worked them in so perfectly.
Infamous and Prototype are both fantastic, as is Arkham Asylum. I would also personally throw LEGO Batman in there.
Haven't played Little Big Planet yet, but everyone I know who has loves it.
Both the new Assassin's Creed and the latest Prince of Persia are really fun puzzle platformers, and while you can blast through them, you can also spend hours running around collecting stuff for fun.