As much as this doesn't belong on this forum... I have to say it...
Slash is the most overrated guitarist of all time. He's simply not that good, buckethead on the otherhand can play just about any genre and play it well... while wearing a bucket on his head. He plays for the music, Slash plays for the money and admits it like the tool he is.
Anyone not familiar with buckethead likes to say he's all speed and no emotion, to which I say, you need to listen to something that isn't "Jordan". Listen to "Too Many Humans" for example, quite possibly one of the most unique and soulful pieces ever. That or "Soothsayer".
That said, I still say Petrucci owns them all, he has a knob on his rack that controls the sun.