Went to Mayhem Fest last summer: In Flames, Unearth, Trivium, All Shall Perish, Machine Head, Megadeth, Godsmack & Disturbed
Saw 5FDP, Hatebreed, All That Remains, and Rains (Rains didn't belong in that group, a lot of people were confused when the started playing)
Probably go back to Mayhem this summer, unless I move by then.