I didn't like either, but Modern Warfare 2 was better in my opinion. I pretty much hated ODST and didn't even bother to finish it. I've never been a fan of Halo games.

Quote from Dark

why would you compare a platformer to shooters

Because Mario is awesome.

ODST, simply because I've never played MW2.
Granted ODST could have used some work. Like giving the main character some ****ing voice acting. And a not-so shitty gun. And a name. Oh, and maybe the ability to fall more than three feet without getting hurt. A good ending could help. Maybe the stupid piece of shit BB Gun of a pistol could be replaced. And, you know, the whole 'machinegun with a scope' shit. And that stupid Commander Bitchalot. And...
**** it. MW2 is probably better.

Halo 3 rules!like i said,im only nine!