If you can continue to use what you're currently using for the next month or 2, if you can wait, then wait. On the other hand, except for a few little upgrades, the next version probably won't be that big of a deal. I think most of the issues with the MacBooks and MB Pros, so you could always just buy a cheap one or a refurb or something, then sell it and upgrade to the new model. I think the new MBs will be out before Vista's official, and I have a feeling you'll be kicking yourself if you buy now, so give it a few weeks.
Vista will run on any Intel Mac, but whether it will run well or not is not is another matter.