Brewology

I agree with all of those, K2 is my least favorite of the bunch.
I can suggest:

LittleBigPlanet (X)
Burnout Paradise
Elder Scrolls IV: Oblivion
Metal Gear Solid 4 (X)
Resistance 1 (X)
God of War Collection (X - Includes God of War 1 and 2, demo for 3, Trophy Support, bonus content for the games)
Uncharted 1 (X)
And Ratchet and Clank: A Crack in Time just came out, haven't played it tho.

(X) - Exclusive

This are mine collection
1. Call of Duty 4: Modern Warfare
2. Burnout Paradise
3. Fallout 3
4. Resistance 2
5. LittleBigPlanet
6.Bioshock2
Apart from this one of my favourite is Bioshock2 it gives you advances bring new depth and dimension to each encounter. New elements, such as the ability to dual-wield weapons and Plasmids, allow players to create exciting combinations of punishment.