The ps3 can do way more than the 360, has a built in BlueRay player(500 bucks for a player), and the hard drive has more space, the elite has 125, but who the heck needs 125 gigs??
That game looks fun, I like the GTA series, have a lot of them, started playing them about 2 years ago...
But really if you ever have the cash, go for a ps3.
I am Sony guy also.( and Ford)