if you missed a performance you wanted to see.. this site has a huge list of the bands with fairly good quality movie files of the performances seperated by song
http://www.sonician.com/live8/list.html a few highlights..
Def Leppard was surprisingly good if you like that kind of 80s hair rock ;)
The Cure
Bjork
Muse
Sarah McLachlan sounded amazing
A-ha did Take on Me but I haven't watched it yet
Green Day was great
Deep Purple
Pink Floyd
Paul Mccartney doing Helter Skelter was a good performance
The Who were damn good
I wasn't impressed with REM and I usually like them
Coldplay
of course U2, Sting, Madonna, Elton John and other big name acts are there too