It's an AMV of "Shamanic Princess" with the background song "Imaginary" by Evanescence.
EDIT (14.12.2005):
Some of you guys don't or didn't know this version of "Imaginary",...
Short Channel 4 documentary from 2001 featuring interviews with designer Karin Fong, producer Chip Houghton and Cooper himself.
Gives a nice insight into what drew...