Jimi Hendrix of course!
One of my favorites
Eddie Van Halen
Eruption is damn intense, especially for it's time, love both songs.
Ritchie Blackmore
This solo still blows my mind, and the riff is awesome. Love his work with Rainbow, Deep Purple and even Blackmore's Night isn't bad.
Tony Iommi
Not one of his most technical songs, but this made a big impact for it's time. Such a awesome dark tone, and the guitar work is still loved by me here.
Steve Vai
Not sure what's best here, his facial expressions or his guitar work....either way, the dude is a legit boss.
Bumblefoot
Weird ass dude, but his guitar work is legit boss.
Number 1, of course comes to mah boy Buckethead
Soothsayer is wonderful. A mixture of soft emotion and fast pace guitar work mixing together really shows his better side as oppose to the popular song Jordan. Too Many Humans is still my favorite song by him though. Just a great deep thinking song, and very relaxing. Songs like that are where I think he exceeds at than anything. Fast paced guitar work is nice and all, but I really love the more mellow side of Buckethead, and every guitarist in general.
Probably forgot a few, but these were the first that I could think of.