As a gamer I find my 360 collection lacking (look at my profile), and since I have a gift certificate that will be expiring this weekend I figured I'd use it to expand that a little... Unfortunately, I just can't decide what to get. Looking at your own collections what games would you recommend?

Please note I have ME2 and L4D2 on PC. I also play pretty much any game type, my only requirement is fun.

Please don't mention Gears (I own the 1 felt was worth buying), Halo anything (I just haven't played one worth buying yet for the 360 though I hope Reach changes that), Fable II (I've beaten it twice and not interested in a 3rd play through), or anything where multiplayer is the only fun to be had, I rarely play mp. I've also played SC: Conviction and will likely buy it on a price drop.

Download some demos and see what you like.

Buy some points and get some XBLA games.

I would recommend Lost Odyssey since you bought final fantasy 13 and crisis core. Lost Odyssey is more like a traditional final fantasy than those two games that you bought. Tales of Vesperia is also another solid jrpg. You should rent or try out infinite undiscovery, star ocean 4, magna carta 2, and the last remnant too because I thought those games were way better than the reviews would have you to believe.

If you like sim racers you should get forza 2 or 3 those games are loads of fun. Resident Evil 5 is a solid game. If you like challenging games the most difficult version of ninja gaiden 2 is the xbox 360 version.  Alan Wake sounds and looks like it's going to be a great title too.

Finally you should look on xbox live for any games that looks like it might appeal to you and download the demos if one is available.

I just got Dead Space, I'm a little late to the party but this shit is scary!

Lay your library end to end instead of upright.
That should extend it.

I dunno, how many. as most the games I would've got on 360 are on PC similar to you

But dead space, is my favorite... if you don't use the xbox 360 controller on your PC, because the PC controls I thought were aweful (But I used a 360 game pad.) And others like Lost Odyssey, like was already said.

demos on xbox live are great though!, if you haven't already done that

The original Bioshock; best game of this gen so far imo, and it's really cheap now.

In no specific order, these are all games worth checking out:

Batman Arkham Asylum
Prince of Persia
Brutal Legend
Shadow Complex (Best Original Live Arcade game)
Crackdown
Ghostbusters
Darksiders
Bayonetta
Assassins Creed 2
Mirrors Edge

The beauty of all the above games is you can score most of them at a pretty cheap price. Plus don't forget Alan Wake is coming out in a couple weeks. It should be a decent title as well.

Batman: Arkham Asylum (though I'd get this on PS3)
Bayonetta (360)
Bioshock 1/2 (PS3 for Bioshock)
Borderlands
GHOSTBUSTERS!
Lost Oddyssey
Red Faction: Guerrilla
Saint's Row II
Viva Pinata

Most are multiplats, get them on whichever system unless specifically noted.