Just installed Vista, still fighting with it atm. It installed painlessly enough, credit for that (apart from filling both monitors with a white background at 60Hz, felt like I was going to have a fit) but I seem to have to bury myself three windows deep just to find an advanced button, which lets me change what I wanted. So much for a more streamlined interface, it's just full or idiot windows which, once navigated past, bring up the same thing we have in XP already.
Example: finding hibernation settings:
1. Right click on desktop, choose personalise
2. Choose screen saver
3. Select change power settings
4. Change plan settings
5. Change advanced plan settings
6. Sleep => Hibernate After => Never or x minutes
Lovely streamlined, intuitive interface design there.
This disables automatic hibernation but still doesn't disable hibernation completely so you can't reclaim that HDD space. To do this:
1. Nagivate to Programs, Accessories, System Tools, Disk Cleanup
2. Choose all files, Vista partition
3. Pick "Hibernation File Cleaner", then OK
You finally get your HDD space back. Really obvious place.