After the demise of Stage6 , I was having a look around for any decent music video sites with hopefully decent sound quality, and I came across this guide.
There's a lot of rubbish here, but there's also some fairly decent stuff. One of my favourites, Fab Channel, is listed here. A large collection of live concerts.
Some may already have seen this list, although it's new to me. Worth a trawl through on a rainy night when you're bored.