Stuck Between acouple of game!!

Hello All,

Well, my brithday is next month (May 10th) and i need ideas on what to buy for my 360, whether it may be games or Hardware even, its really hard cause theres tons of awsome games but i only can choose 1 of them (I reserved GTA IV,Halo 3 and Assassin's Creed)

+Games I Have+

Gears of War

Rainbow Six Vegas

Splinter Cell DA

Saints Row

MLB 2k7

Fight Night 3

WWE SDVR07

Test Drive Unlimited

soim looking to get 1 more added to my collection..so what do you guys think i should get? Thanks For The Help!

*Note* im getting Forza Motorsport 2 also so anything besides that.

rainbow six if you have live....

oblivion or gears of war if you don't have live