Your upgrade path , spelt out in stars.

On Monday I bought a new computer, my first new machine since 1999.
I was an early adopter of NT5 back in 1998, and when it subsequently morphed into Windows 2000 I upgraded my home machine from NT4 as soon as I could get hold of a copy.
All well and good, there were strong reasons - the power of an server-strength OS with the PnP GUI of a desktop OS.
But since XP and Vista, there haven't really been any strong reasons for backing up every my entire machine, wiping it then starting again with a new OS.

This new box has kinda removed that hurdle for me by coming with XP Pro pre-installed but y'know what?...there's next to no appreciable difference, apart from the additional annoyances of turning on things that had no real business being turned off by default.

This machine is more than double the benchmarked performance of my previous beast, but I'm just not seeing the performance benefits. Maybe there's three or four seconds shaved off at boot, three or four at shutdown, but that's it.
What gives?
This all justifies everything I've ever said about upgrading - if it works, leave it alone. Unless you have a very very strong reason for moving to the next version point, why cost yourself the money, time & effort? There are usually no returns, damnit!