I watched Kaibutsu Oujo today (first airing), and the ending theme was by Ali_Project.
Which made me think that every anime I`ve watched and liked has had their OP or ED by Ali Project.
Does anybody have a musician that they seem to cross-encounter time to time when watching anime? :X
Well, it's no coincidence, but a lot of the anime I like have music by Yuki Kajiura...
ALI PROJECT tends to show up a lot - Noir, Avenger, Rozen Maiden, .hack//Roots - plus they just have a really distinctive style.
I think I rather prefer KOTOKO's OP themes, though.
As for bgm composers, Taku Iwasaki and shows up in the strangest places, and everyone knows Yoko Kanno. But there are a lot of composers that seem to show up once or twice and are never heard from again. Yoshihiro Ike did a really cool Ergo Proxy soundtrack and apparently he did Kamichu, too, but little else of note; neither composer from Death Note's great soundtrack has more than, like, three shows I've seen to their credit, and all of them small-time ones at that.
I think that, like most businesses, there are some big names and go-to groups that get lots of work, but I don't think they're necessarily the best all the time.
I actually have found series to watch based on musicians and what they have played in (i.e. watching ARIA from ROUND TABLE's ED). KOTOKO performs quite often, among other I've singers.
Since Horie Yui practically plays a role in nearly every recent anime series (she or Hirano Aya), she tends to sing a lot of OP/ED songs.