Is this song, which I confess I had never heard of before I saw Kill Bill, Vol. 2, but it was probably the biggest reason I wanted to soundtrack.
Try to ignore how ridiculous that hat looks on not-a-mariachi.
I discovered quickly (as mentioned in the above video) that it's an update of a mariachi classic, which, having heard, I also love.
The band responsible for the new version, by the way, was started by Robert Rodriguez to do music for some of his movies. This makes my inner music snob/cynic scoff. But, as previously noted, I love this song. They're called Chingon, which more or less means "bad ass", which is reason enough for me to love them (speaking of, Dad, could one feminine-ize that noun?). Finally, the clips of the rest of their stuff available on their website are pretty good. Based on that, I've decided I can continue to like it.
Which is good, because -- also mentioned above -- I freakin' love this song.