Sell my 360 for used ps3?

May be...

I own a Xbox 360 with hard drive, 3 controllers, cables, and halo 3, cod 4, 5, gta 4, assasins creed, halo 2,

If sold those to gamestop, how much would i get.

And if i do get a good price, should i buy a used ps3?

Which gaming console is better gaming wise, not game wise cause the games that are not multiconsole, are not that great anyway. so is it worth to sell 360 or or keep 360?

I suggest you keep your 360. Gamestop is a lowballer, they will rip you off. and besides, almost all of the good games have their 360 version and ps3 version. also, you have a very good game collection, it will be a waste of money to sell them. i suggest you just buy a used ps3 while keeping your 360. but, if you really inted to sell your 360, getting a used ps3 is ok. Gaming wise, 360 and ps3 is about the same, but ps3 is better quality-wise and feature wise ( ps3 has a blu-ray player ) unlike 360.

I would keep what u had....if u really want a ps3 PLEASE do not give it away to game stop they r a rip off just looking to make a lot of $$$ off of u