Not one of the anime girl shmups, but still a fucking radical ass game.
I picked up Ikaruga at a Gamestop a few months ago for Gamecube. I'd been emulating the Dreamcast version for awhile, but it had some emulation hiccups. I nearly had a heart attack when I actually saw it in the store (THERE WERE EVEN TWO COPIES!)
And then there's the classic freeware game Warning Forever, an endless succession of boss battles where the subsequent bosses evolve depending on how you beat the preceding ones.