I'd have to agree with Jimmy14 above the spec just to run an OS is ridiculous, all I ask from my OS is that it's secure, stable with enough drivers to run my tower without having to install drivers for modems or sound cards XP does this (I'll give it a little lee way on the secure bit;) ) and more, I'm going to be looking at upgrading my PC next year will I bother with Vista, I don't think so.
After having a shot of a macbook and macbook pro I might just move to apple in 2007 especially with them releasing leopard. I'm quite fed up with windows and its security issues. I've also played around with vista pre rc1, RC1 and RC2 but I don't see a major difference in technology with Microsoft spending £10 billion on developing it.
I paid £320 for 16 Meg of memory to run Windows 95 10 years ago - I went from 4 Meg that was running Win 3.11. I recently upgraded my Pc to run Vista by increasing my RAM from 1to 2 Gig & upgraded my Graphics card to 256 Meg to run Vista which cost me much less than my upgrade 10 years ago!