I just bought a mutha f-ing 360

[I LOVE GIGGS]

1- Gears of Wars and Mass Effect
2- Bioshok and Halo 3
3- Enchanted arms or Blue Dragon ( Eternal Sonata also a good game )

Oblivion , Dead Rising , PGR4 , Lost Planet , AC

XLive games is the best in my opinion ..
Like Halo or GoW or CoD4
you should try Lost Planet..
very good game .. may be only 12 hours
but online really good and fun