I've installed Vista on my MacBook via Boot Camp. So far it's running, but there's a few bugs.
The battery seems to be draining really quickly according to the power meter, it's only been on for half an hour and it's sitting at the 65% mark. Also, I can't seem to get the drivers for the wireless networking card, the mousepad, the camera, or the sound card.
Might downgrade it to XP for now until it gets sorted in Leopard.