I watched the first episode of a weird anime today, called Karakuri Zoushi Ayatsuri Sakon (aka Puppet Master Sakon). The premise essentially involves murder mysteries solved by a young man and his bunraku puppet, who happens to be alive [Edit: or not...? See the thread for details]. (Yeah, I know. Please consider that I am also into an anime about a boy, a board game, and a ghost from the Heian period.)
As the opening credits began, filled with beautiful traditional images of Japan, I listened to the lovely music and thought, "This is really cool!" The singing started out gentle, but then it got more intense, and suddenly I gasped (yes, out loud), "That's BASARA!"
I hurried to check the credits...and sure enough, the OP was done by Humming Bird, with vocals by Fukuyama Yoshiki.