MS recently released the hardware requirements for Vista, and obviously they are well below what you would really need to run a decent system, but Winsupersite have a more detailed look at the requirements
here
Will be one of the first to make the move over, but will also have a backup system for the inevitable grief I will get for being one of the first later this year.
Interestingly, I read recently that the reason Vista has been delayed is nothing to do with MS being late, rather the major PC vendors require more time to create their builds and go through testing. Dell have a 3 month turn around on every one of their updated builds! For a new OS, they'll probably need more.
Also, for anyone on Phuket, I can get hold of the latest Vista builds from MS if anyone is interested in taking a look sooner rather than later