I'm meant to be going Download this year for my mate's stag, but it seems to have the worst lineup of all the festivals this year! I think the only band i'm HUGELY interested in on the whole lineup is Funeral For A Friend, and i've seen them 6 or 7 times now so even that's not much of a draw. Some others like SOAD and LP might be good fun, but not really what i'd pay a huge chunk of money for.
Some class bands at Glasto imo. For my tastes, particuarly Biffy (less keen on their newest albums but was a huge fan on the first 3), Jimmy Eat World, Pulled Apart By Horses (defo one of my fave bands of the last year-or-so). QOTSA would be great to see in a festival environment too i think.
There's some great bands lower down the order at Sonisphere too. Not keen on the big metal bands they've got playing, but lots of goodness on the lower bill. And they've got Biffy as well i think.
I'll defo be going to 2000 Trees again this year, so long as it's not sold out before my student loan comes in! Some of my favourite bands playing that- Tall Ships, And So I Watch You From Afar and &U&I especially, with a load more good bands playing and a load more to be announced. Had an amazing time there last year.