Fucking 360s. I have one (my second after my 1st one died), but will always buy the ps3 version of a game if it's available. Sorry I can't help with your problem but thanks for the opportunity to rant a little!
I'm not familiar with the 360 but to my knowledge there is a way to add a bigger hard drive to them. If such a thing is possible then it stands to reason that there could be either a) some connection for its current hard drive that is loose/breaking, or b) the hard drive you have is going kaput. If the latter is the case you should be able to replace it from the things I've heard, but I don't know for sure. I'd suggest you Google it, but if you search "360 problem" you'll probably get a million links about the RROD which won't help. Good luck in your search anyways.
Regarding video games right now I spend a healthy (or unhealthy) amount of time playing Black Ops co-op with my roommate (us 2 vs 8 bots on random maps in TD). I'm not a COD guy really, but the PS3 is seriously lacking in Splitscreen Coop shooters. When I'm done building a new rig I will be lost in BF3 forever methinks. The clan I'm in is into the thick of it, but I haven't bothered with it yet until I get a PC upgrade to power it half decent. Looks deadly though.