I would sell the modded 360 to someone you know or on craigslist.com
Your not going to get much from GameStop for trade-in value, let alone that modded 360 is out of warranty, so your screwed. Your better off selling it to someone who is in need of a 360 and wants a modded one. I know several people in my area that wants a modded 360, like I said. Ebay or Amazon or even craiglist is your best option.
And its a really good thing you want a PS3, because the PS3 is about to have a huge load of software soon!







