chemcat and snowdragon, i'm pretty jealous of those shows. wish i coulda seen all of those acts live.
i've seen some great live music though:
paul mccartney @ citifield
Phish. many times, but 3 particular highlights were the 3 day camping festivals in Limestone Maine and the one at Watkins Glen, NY (just 2 weeks ago), and a great show at Bethel Woods, NY, @ the site of woodstock.
The Who @ jones beach, when john entwistle was rocking
Flaming Lips, in Massachusetts, I can't remember the venue. Wild, absolutely wild. You could be sober as a nun, and you'll feel like you took hallucinogens...
Soulive always kills it, but the House of Blues in Boston, the Tufts University auditorium, and Brooklyn Bowl were 3 great ones.
Christian McBride, when I was a kid, totally blew me away. I was just learning the bass, and had no idea someone could play it that way. It was eye-opening.
Chuck Berry, I think it was a county fair or something, on Long Island. He was pretty old when I saw him, but he was still on fire. He was a little forgetful, but he could still sing, wail on the guitar, and keep the crowd on its feet.
Snoop Dog w/The Red Hot Chili Peppers, Randalls Island, NY. The sheer novelty of it would give it a place on my list, but it was actually surprisingly good. They did some RHCP songs, some Snoop songs, and some "mash-ups" that combined their songs with eachothers. Pretty cool, and they worked surprisingly well together.
Radiohead. Radiohead shows are like religious experiences. Indescribable beyond that.
I'm sure there are others that blew my mind, rocked my face, or were otherwise note-worthy, but these are the ones that come to mind.