My list of who I've seen is far too long, and probably explains why I have fairly poor hearing!

Radiohead
Bob Dylan
Meat Loaf (first ever gig)
Muse
Red Hot Chilli Peppers
Oasis (it should have been twice, but only once as we went to what turned out to be their last ever show at the V Festival, and my mate took a bad trip. He spent fifteen minutes promising to buy tickets to their next show as I carried the fucker back to the tent....I'm still bitter)
Foo Fighters
U2 (worked the bar at the Millenium Stadium, they were good, but not £80 per ticket good!)
Gang of Four
Sham 69
30 seconds to mars
Manic Street Preachers

Those are the ones that come to mind immediately, and I always geek out whenever Eels have a new record or tour, and see them a few times on each visit.