I posted over on my gaming blog about all of the reasons you don't want to upgrade to Microsoft Vista right now. However, if you are in a situation where you MUST upgrade for some reason, then you are probably reeling at the prices of Windows Vista. Of course, the upgrade price is a bit more reasonable, and it turns out that you can do a clean install of Vista onto a new machine despite statements from MS saying otherwise.

It's been posted around in a lot of places, but the basic outline is:

1. Boot your machine from the Vista Upgrade DVD
2. When asked for a Product Key don't put it in. Uncheck the box that specifies to activate automatically
3. Hit the Next Button
4. Choose to do a Custom install to do a clean installation
   
5. Install Vista. This will be a Trial version, but you're not done yet
6. Once you reboot into Vista, you cannot activate because you have a Trial version
7. Insert the Vista DVD and run the setup.exe program on it
8. This time enter your Product Key when asked
9. Do an Upgrade installation

Vista will now be cleanly installed and you never even had to show it your XP installation.

Note that this might put you in violation of the EULA, but if you did have an XP installation, there probably won't be any problems.