If you were ever curious where I get the music for most of my videos, I tend to start with The Kleptones and end with Mash-Up Your Bootz. The Kleptones always have great tunes, and most people on the internet have probably already heard them. Mash-Up Your Bootz on the other hand is a mixed bag, be prepared to rummage through some horrible crap before finding something amazing. You gotta dig, bro.
My current favorite.