I would never upgrade over any Windows system. You're asking for trouble really as Microsoft usually have made lots of changes between the versions which will come back to haunt you. XP changed the USB stack as an example so you'd need to go and find new drivers for any USB devices you've got.

I agree that it's annoying having to redo all of your configuration and check that everything works but it will be much more stable. I always find that I end up with a leaner configuration as well as I don't install the applications or drivers for things I no longer want or need.