I have Vista x64 on my MBP. The Leopard install disk does come with all of the drivers that are needed. The problem is, a few of the drivers (like Broadcom's driver for the Airport Card) are not update to date. So you will have to update a few of those drivers. HOWEVER, Vista does a piss poor job on finding updated drivers because it only searches Microsoft's driver servers, which means you'll have to hunt.
I recommend searching Apple's Support forums for the driver links to use. Luckily, most of the people who post on those forums are knowledgeable enough to give you help.
Boot Camp hasn't really been updated all that much, so don't worry about trying to depend on Apple to give you the best drivers. What I have seen is the only time Apple releases an update to Boot Camp is if there is a major driver issue with connecting to Apple specific peripherals (ie. iSight Camera, back lit keyboard, etc).
Good luck and happy hunting!