Here's the list so far. They should be adding a few more bands soon. I think I'll go just for one day on the best day. I've seen just about everyone on this list except for a few.
ABORTED
ALESTORM
AMON AMARTH
BLIND GUARDIAN
DEATH ANGEL
DEATHSTARS
DESTRUCTION
DIE APOKALYPTSCHEN REITER
DIMMU BORGIR
DOWN
DRAGONFORCE
EDGUY
EQUILIBRIUM
EXTREMA
GRAVEWORM
HACKEYENED
HATEBREED
HOLLENTHON
KATAKLYSM
KEEP OF KALESSIN
KREATOR
LAMB OF GOD
LEGION OF THE DAMNED
MY DYING BRIDE
NAPALM DEATH
NIGHTWISH
SATYRICON
SODOM
SONIC SYNDICATE
SUIDAKRA
TESTAMENT
VADER
VISIONS OF ATLANTIS
ABORTED
ALESTORM
AMON AMARTH
BLIND GUARDIAN
DEATH ANGEL
DEATHSTARS
DESTRUCTION
DIE APOKALYPTSCHEN REITER
DIMMU BORGIR
DOWN
DRAGONFORCE
EDGUY
EQUILIBRIUM
EXTREMA
GRAVEWORM
HACKEYENED
HATEBREED
HOLLENTHON
KATAKLYSM
KEEP OF KALESSIN
KREATOR
LAMB OF GOD
LEGION OF THE DAMNED
MY DYING BRIDE
NAPALM DEATH
NIGHTWISH
SATYRICON
SODOM
SONIC SYNDICATE
SUIDAKRA
TESTAMENT
VADER
VISIONS OF ATLANTIS