If you can't wait to rush out and buy a brand new retail copy of Vista when it hits the shelves, you may want to take a look at the new licensing that Microsoft is introducing first. “Restrictive” isn't really quite the term, accurate though it would be. “Bizarre” would fit better, and some of it is outlined here. One of the oddest things is Microsof'ts stance against virtual machines. While allowing Vista Ultimate and Business to be run in a VM, all other versions are barred from it. Meaning if you are running Basic or Premium in a VM, you're violating the license.
Vista will also strip OS functionality should validation fail. What people feared with activation in XP is now coming true in Vista. The OS will periodically “validate” itself, and if it finds that you are a dirty pirate it will limit your use. It also only allows you to transfer a license once. Meaning, if you have a Vista-equipped PC and you rebuild it, you must transfer the license... and then never again can you repeat that process. Some people are used to replacing many components of their PC quite often, going through an entire rig in mere months. Enthusiasts beware.