Powered by HULU, the excellent hi-def version of YouTube (if you watch reruns of "The Office" on Hulu, you know what I'm talking about), MTVmusic.com does what MTV used to do: play nothing but music videos.  What a concept!  Its too bad Pitchfork is going to take credit for the resurgence idea.And as much as everyone bitches how MTV is no longer about music, the internet is really the perfect setting to host music videos.  The video is supposed to be consumed in little p...