your x360 will break, so go with ps3
sure it has no games now, but that'll change in the fall, they have like 6 exclusives coming and they have something for everyone
online: warhawk, haze, socom
offline adventure: heavenly sword, uncharted, rachet and clank
casual: singstar, home
if you decided to get a x360 anyway, don't be surprised if it breaks, and just make sure you get a store warranty so that you can exchange it with a new one in the store, dont mess around with ms's warranty service, they'll send you a refurb one and it'll break again within 3 months
or,
you can get a RRoD x360 on ebay for $160 or so, then do an x-clamp replacement surgery, it's pretty simple but it might take you a day if you're not used to it, if you could fix it you got yourself a $160 x360, if it doesnt work, call microsoft and you might be able to get a working replacement for $140 ($140 + $160 = $300, same thing right?)
you can find the xclamp guide here:
http://forums.xbox-scene.com/index.php?showtopic=599216, just use lawdawg's method