Guitar Hero may have introduced a lot of people to him but a fair amount of the stuff mention in even this thread would never belong in Guitar Hero. It'd be like, 2 or so years down the road, saying DT is overrated because Panic Attack is on Rock Band. Hell, even WITH Guitar Hero he's still not that well known. I think more people played Jordan and went into rage mode instead of going "woah, this song's hard so Buckethead must be the bestest guitarist ever" and, even then, the kids who do that are going to go crazier over Dragon Force than him. Actually, I know quite a few people who have GH2 but have no idea what I'm talking about when I mention Buckethead.
I'd be interested in hearing what albums of his you've listened to, if any.