Thanks for the reassurance.
One more thing. Doesn't Vista require more power than XP? Wouldn't the computer run faster if I were to use the XP portion while turning off Vista?
First thing to do is track down all the XP drivers you would need. If you can't get drivers to run the machine on XP then it's a moot point. If you can, then burn 'em to a CD or store 'em on an external drive so you have 'em if you decide to put XP on. I got a PC with Vista 32 bit before SP1 and it was quite a bit of work to quiet the HD down. My 2nd Vista PC is 64 bit with SP1 and the services are set up better so it doesn't hog the HD as much. Still there are some things you can do such as turn off Windows Search Indexing and use another search app like locate32, turn off indexing all your media files and use other media players like Winamp or VLC media player. That type of stuff.
Vista does work your HD much more than XP. No question about it. If you do use locate32 disable "monitor file system changes" or it will run your HD like crazy every time you copy a big block of files(like if you backup to an external drive or whatever.)
On the plus side if you use VistaGlazz you can do a lot more with themes than in XP. The exploding windows are fun(seems lame but when I turned them off I missed 'em so I turned 'em back on.)
Vista is definitely way better with SP1 than without. My first PC won't take SP1. I tried 5 times to put it on and it rolls back every time. But I've worked around most of the problems and individual updates can be put on so it's not all bad.