360 Collection of Games, any good?

As it stands, I think I love my collection of 360 games - I will list them, and if you have any suggestions please let me know. (I just got Fight Night Round 3, been playing non-stop with a buddy for 3 days straight, go BIG E!)

Mass Effect,

Call of Duty 4,

Halo 3,

skate.,

Madden '08,

Fight Night Round 3,

Lego Star Wars II

(didn't get Oblivion, I may though - I have on my pc but it runs like absolute crap, I've never seen it in full glory, worth it?)

Played and beat it, not a must own IMO.

One playthrough, and I felt I was done. :)

I absolutely love Mass Effect, and CoD4 looks really intense, but i havent played anything else on the list nor had the interest.

I also did just get my 360 last month though

Bioshock,Gears of War,and Assassins Creed is what you need IMO

Here's mine-
Bioshock
Halo 3
Kane And Lynch
Call of Duty 4
Mass Effect
Assassins Creed
Ace Combat 6
Gears of War
Guitar Hero 3
Rock Band

I don't have that many, but they're all really good:

The Orange Box

Assassins Creed

Halo 3

Gears of War

Splinter cell: Double Agent

Ghost Recon Advanced Warfighter 2

Just six... Ah well, I'm getting Bioshock, Call of Duty 4, Mass Effect, and Oblivion for Christmas