Glastonbury you have a wide range on Genres bands which headlined 2011 Coldplay,U2,Beyonce, Elbow, Wu-Tang Clan So you have rock, rap, hip-hop, dance, ect ect
Download. Bands which headlined 2011 The likes of Def Leppard,System of a Down, Linkin Park, Pendulum, Alice Cooper, Rob Zombie are headlining so It's mainly rock music.
Depends which music you're into
Depends on what music you like, really :)