I guess this is one of the changes they made to always keep Windows running smoothly.
When Windows Vista is installed it automatically sets up a schedule to defragment your hard drives once a week. You no longer need to remember to defrag your hard drives once in awhile in order to keep your system running efficiently.
Now, this is a feature that I was a little surprised they didn't add in XP, but I'm glad it's here in Vista. One thing I always thought was a little interesting is if you check the "Disk Defragmenter" just after a fresh Windows XP install, it will always say you should defragment the drive.
I have the Vista x64 Realtek AC'97 audio drivers installed; so my sound works now. I think these are beta drivers so we'll see how they do. I'll have to check every once in a while for updated drivers.
I also have all my software installed and everything seems to be working perfectly.