OP-Baccano. Yes, ANOTHER anime op. I finished Mushishi (and it was great), and have started into Baccano!, written by the same guy as Durarara!!, and animated by the same studio, and with the same style of opening. So far, it’s anachronistic, but damn stylish.
Sayonara Zetsubou Sensei ¡3 Opening Mix!. Some crazy man took the OP songs from Sayonara Zetsubou Sensei and the sequels Zoku and Zan, and the opening scenes from every season except Zan… Bangaichi, and mixed them together. Holy crap. If you’re a fan of the series, then this is going to blow your socks off. Oh, and, as with the series in general, NSFW. Especially the last minute of Nozomu making himself taller.