I used to think that Yngwie was the fastest, but I heard this guy Michael Angelo and he's insanely fast! He plays a double neck guitar, one right handed and, you guessed, the other neck is left handed. He does some harmonized double-hand arpeggios that really impressed me. But I'm dissapointed with his composing skills. He sounds way too hollow! And he cheats: he uses string dampeners to keep the strings quiet and tons of digital effects... :-(

Tony MacAlpine is brilliant in many senses, but his piano playing sucks. Anyone that has heard good Chopin records (like those from Deutsche Grammophone) knows that MacAlpine sounds too harsh at Chopin.

Yngwie and Vai are my all-time favs, but both of them bore me if I listen too long to their records.