Asian Kung Fu Generation
Not well known outside of anime circles, but the band name says most of it all. Here's a band which I think captures the awesomeness of growing up with Kung Fu Movies at your fingertips, and perhaps one or two sparring matches between brothers and sisters. Some of their best hits have ended up as part of several intros to Naruto. I'm not partial to animes that start dieing down with filler but I think there's a good portion of people just watching for those first couple minutes in with this band rocking it out. No doubt other animes clued in, including Bleach.
If you really want a good snippet of their tracks they've released an album of their greatest hits. Talk about a hidden gem.