If you buy a new computer that comes with Vista, you may want to consider buying a Mac instead. You have to learn a new OS either way.
We have an MSDN (MicroSoft Developers Network) subscription and downloaded all the versions Thursday as we will have to start testing the CPS (Customer Programming Software) that we develop here for the Motorola portable and mobile radios. What's cool is, I get to order all sorts of new PCs to run Vista on!
I've been playing with the beta and release candidate versions of Vista for about 6 months and it does look cool but if you want the full bang, you need one of the latest PCs with at least 1GB of RAM and definitely a video card that supports heavy graphics.
On my personal machines, I will wait until well after the first service pack to upgrade. btw, I understand Microsoft is already working on this!
