I haven't seen many shows but these 2 are my fave guitarist I've seen live:

Omar Rodriguez Lopez.... yeah I know everyone says he's sloppy, but he just put on a really really good show, Dancing and throwing his guitar on his back. Not to mention I love the Mars Volta, so I was in heaven for an hour.

The guy who plays George Harrison in this Beatles cover-band called Liverpool around here. I'm pretty much always front row (My girlfriend and her friend run the fan club) and he just rips out those classic Beatles solos like he owns them. I'm always trying to see what he's doing. I love how he uses the mic stand for a slide for the orchestra crashes on "A Day in the Life" pure sugar.

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I Like to go scree scree boop