meh.... I was the same way when I got my 360, being a Sony fan, most of my 360 games just sat there(and some still do) one day I just dived into my small 360 game collection and blocked out all my other systems, and I started enjoying playing my 360, don't know if this method will work for you, but can't hurt.
it seems that you just have more games/friends for your 360 which means you probably will put more time into it.(like me with my PS3), like twerstern said you're not the only one.








