SRSLY, anyone thinking of going to Vista (which seems to require a min 256M of RAM, WTF?) should either stick with XP, or just accept the real future and load up with an off-the-shelf version of Linux. For the money, just buy a copy of Redhat; you get support and a great OS.
Microsoft has REALLY tried to fuck our asses this time. Fuck them back. Sure, they'll probably strongarm the businesses into upgrading, but with all that DRM crap, you really ought to think carefully about letting such controls onto your computer.
For those of you who "have to" upgrade (either by buying a new computer with no XP option, or work requirements), then I wish you well. All omelets require the breaking of at least a few eggs.