I think what I like about Metalocalypse is that they parody the whole Metal scene, and as a fan I personally love that. If musicians get too serious about their craft, it becomes more tedious to me. People have to be able to laugh about their art, and Metalocalypse in my opinion takes on the darker stuff. Tenacious D fills in the gaps for the lighter Metal scene.
That and Brendon Small is a bloody genius. Like the show or hate it, it's hard to dispute that fact.
At any rate, you guys have a good night. I'ma hit the sack. With my fist.