There are a lot of excellent solos out there, but in my mind, nothing will ever touch Hendrix's "Machine Gun" from the "Band of Gypsies" album. There are a lot of things about it you could critique, but the work had a passion to it that has never been reproduced. Of course, that was Jimi's magic. He wasn't the most technically correct, accurate or proficient player, but you couldn't take away the soul of the man, which was glaringly apparent in his sound. Practice his stuff 'til your fingers bleed, buy all the same equipment, run it the same way in the same venues, and you still won't get anywhere near it. Kinda like Janis Joplin during the same period. She really wasn't that great a singer, technically, but nobody has ever really been able to touch the passion she brought to her art. Closest I've heard since is that angry bitch, I can never remember her name, but I'll bet you know who I'm talking about. Everybody always does.
I just remembered - Alanis Morrisette. Man, she's got bitter in the bank, eh? <grin>