I'm with sushi2 on the "Got Melee" one, it's really good.
Epochof7's
Secret Agent Man was one of the first that I saw and I still think it is amazing, I highly recomend the download (despite it being a quicktime vid

). - Spriggan with the james bond theme remix
SpPANDA's
Session 6 fills the void is pretty darn good. - My Goddess - A perfect circle
Feanor's
DBZ Vogue is wonderfully funny, if you haven't seen it you
really need to download it. I think you can tell what the anime and song are from the title
and
Gurukast's
confused is very well done. It uses Boxcar racer and FLCL.
Oh, and can't forget "Tainted Doughnuts"

One of my all time fav's.