Got a 360, need some games.

Hey guys,

i just got a xbox 360 (60gb) with halo 3 and i also have 1400 gamers points, and 1 yr xbox live.

i was wondering what games i should get for it other than halo 3, i am thinking about gears of war but i am not sure if it has good online since i am really into online.

i have cod4/orange box/burnout for ps3 so dont want to get it again for 360.

any suggestions would be awesome!

thanks

also gamertag: gold33w0lf