Download is the place to be this year I think! I prefer Download to both Reading/Leeds and Sonisphere. On the one hand; Reading Friday and Sonisphere Saturday are both incredible; but Download is the better across the whole weekend.
I'm still considering daytickets to both Soni and Reading but Reading is less likely as it's really far (Whereas Knebworth is really close to me, so is possible) Obviously it all boils down to my money situation at the end of the day, too.
Reading -
My Chemical Romance
The Offspring
Rise Against
New Found Glory
Jimmy Eat World (Although i'm seeing them support Foo Fighters so no big deal)
Muse
Enter Shikari
Sonisphere -
Metallica
Megadeth
Sum 41
Kids in Glass Houses
Biffy (Likewise though, seeing them support Foo Fighters)
Slipknot
Limp Bizkit
Motorhead
Fozzy
Sum 41
Download - (not including clashes, so would be an even longer list if it were to include Pendulum, Korn, FFAF etc)!!
Def Leppard
The Darkness!!!
Alter Bridge!!!!!!!!!!!!!!!!
Thin Lizzy
Puddle of Mudd
The Damned Things
System of a Down
Avenged Sevenfold
Hollywood Undead
Linkin Park
Bullet for my valentine
Disturbed
The Pretty Reckless
Bowling for Soup