best possible games to have on a xbox 360 wishlist

my friend just got an xbox 360 from bestbuy and i was wondering what are the 4 best games you can get on xbox 360 i told him GTA 4, HALO 3, Gears of War, and Oblivion but he wants your personal choices. he likes a bit of every game which makes this thread very flexable

Have your friend considered Call of Duty 4?

Call Of Duty 4: Modern Warfare

Grand Theft Auto IV

Halo 3

Rainbow Six Vegas 2

The Orange Box

Gears Of War (Or wait for GOW2)

Rock Band

Burnout Paradise

Mass Effect

Assassin's Creed

FEAR (OLD, but fun)

MLB 2k8

I probably missed some because the Xbox 360 has many, many good games, but those are the best I can think of... Oh and dude tell him COD4 quickly!!!