Thinking of getting Vista? Here's tips that may make your life easier!
1. DO NOT BUY THE UPGRADE VERSION. Just don't. If you ever have to do a clean install, you will be royally screwed. Pay the extra cash for the full version of Home Premium (most people don't need Ultimate).
2. Run the Upgrade Advisor from Microsoft's website. And then check the rest of web to see if there are any incompatiblities with your software and hardware. The Upgrade Advisor doesn't catch everything.
3. If at all possible, put Vista on a separate HD or partition, and run it in a dual boot config with XP until you are sure that Vista is working OK. I'm not saying that Vista installs always go wrong, it's just when they do, it's nice to have XP to fall back on. (Did I mention that, officially, there's no way to unistall Vista?)
4. BACK UP YOUR DATA! You should be doing this even if you aren't upgrading to Vista.
5. If you are going to put Vista overtop your XP, uninstall any Antivirus, Diskbackup, DVD/CD buring software or similar programs. Even if they are Vista Compatible, even if Upgrade Advisor thinks they are OK, take them off and reinstall them after you install Vista. If you know what you are doing, turn off all startup programs and unnessary services with MSCONFIG.
6. DO NOT LEAVE YOUR VISTA INSTALL ALONE! Do not walk away. Monitor your computer while Vista is installing, especially if you are upgrading. It is boring, but if something goes wrong you will be there to see it right away.
7. When you finally do get Vista installed, avoid Purble Place. It will tarnish your soul.