No worries
I relucantly switched to Vista after being a avid dissident of all MS products for years. The new OS arrived and happily after 4 months using it for both work and pleasure solidly I have had very few complaints, the new interface is a refreshing change and despite the lack of overally driver support I have managed to get every periphial I use (gathered over the past 3 years) working without too many issues.
The new service pack went on for me without any issues, the only problem I found was that after the installation I had to reinstall the webcam driver for my Dell laptop despite it being the same driver as Dell originally installed.
So all the sceptics, I am unsure if you have ever used the OS or if you just like seeing your unguided voices in print on websites but give Vista a chance, it is not nearly as bad as its press of late.