What are best DLC for rock band on Xbox 360?

I have rock band on xbox 360 and have many DLC. I'm looking for the best content. I already have: Gimme Three Steps, Roxanne, The Kill, Attack, This Aint a Scene, Sick Sick Sick, Saints of Los Angeles (dont know how to spell), Every Mettalica song, CrushCrushCrush, Bhetovens C*** (once again dont know how to spell), and Fortunes Son. I beat the game on expert for everything except singing and im looking for a challenge.