One big thing that helps,
Go to Control Panel, Go to User Accounts, and turn User Account Control (UAC) off. Have yey to have to run anything as Adminstrator after doing this. And I don't have windows asking 10,000 times if I really want to do this.
Also, this helps for Vista users to tweak Vista's configuration to get more out of it than the stock settings.
http://www.blackviper.com/ Also some XP tweaks here too. I used it alot at first when I installed XP on my old rig.
Gimpyguy, most likely the shift to 64 bit, is the ammount of memory supported. Even my little Home Premium version will allow a max of 16GBs of ram. And the Ultimate version will let you go up to 128 GBs. Even though I don't know of any ram out there that comes in 4 gig sticks or higher yet, but it isn't too far off I'm guessing.
The shift to Vista, is purely business. Develope a new OS, and quit supporting the old one, so you have money coming in, or you go the way of the dinosaur. I liked XP once I got used to it, but I liked 98se the best for ease of tweaking and stability. At least the shift from XP to Vista wasn't as much a culture shock as it was going from 98se to XP. That was a struggle. It really isn't that far removed from XP, and it only took a couple days to get used to, compared to the weeks I struggled when I first got XP.
I just didn't care for the stock Vista setup with all the automated features B. Gates and company think you should have running initially, but I guess that's done for the home user that wants to turn it on, and not have to mess with stuff, or even cares about what's running on boot up.