XP looks "nice" if you have an aesthetic sensibility strongly reminiscent of Fisher Price toys.
(OK, to be fair I liked the new buttons and tabs a lot, but the giant plastic-y window borders were so awful I shut off the whole "Luna" theme)
I talked to a guy recently who is working for MS on Longhorn. He's on 3 projects: glitch-free media playback, the new full-3D drawing system, and a third one he wasn't allowed to talk about. So maybe there's some hope for revolutionary features yet.