i don't see andres segovia or christopher parkening on this thread, but they should be here. segovia was one of the grand old men of classical guitar, and i remember hearing christopher parkening in concert when i was a teenager and being inspired beyond measure even though at the time i hated classical anything - but he went beyond all that.
i love watching michaelangelo play - i have an instructional video of his (of all things) and it's a crack up to watch. my friends watch him and say "that's done by fast forwarding the video" *LOL* that mutha is FAST!
if you live in l.a., alan holdsworth does occasional free in store performances at carvin on sunset blvd.
if you love hard crunchy guitar, pat lachman from deiselmachine and halford is pretty fucking good
http://aramis.dieselmachine.net/main.html