Linux though is now my work OS i need it for my programming as the compilers arent as good or not available for windows, i also use it for some general browsing as its quicker and malware free.
Alot of the largest companies didnt even use XP up until recently they stuck with 2000 with old hardware, a good example is BP they still used 2000 up to only last year on their systems and thats pretty much as big a company as you get and lots of other non tech companies are old windows users like them. So new hardware is a progression as alot need it anyway companies often tend to understimate the need for a decent computer so Vista on that front may not be a bad thing for the end user. The difference ive had when i went to uni from using crappy business standard dells to the Sun, apple, HP and hand built more powerful systems they have in abundance was huge they understood that more powerful PCs go hand in hand with productivity.
Now older systems are fine if you dont have a choice and linux is a good choice for systems like that especially if you dont need specialised windows software or you need specialised linux software. But its a bit of a pain in the backside at times it requires a little more training for people to actually use it and perform basic maintenance there is little left that linux cant do but its not always as easy to do as it is in windows in fact it almost never is just as easy.
Vista isnt bad at all, fancy UI is actually quite nice very clean and easier to use its not all looks its functionality is greatly improved. Speed normal use its just as fast havent tried it with games yet. Its either going to be really good or really bad. Performance is good and my system is decent but it isnt high end anymore (gig of ram, 3200+ A64 with an x800xl) and apart from the gfx card i would expect any newish system to have at least the same in terms of CPU and memory and i dont need the translucent effects(they arent all that good anyway it feels like they have been dumbed down a bit). Other features are pretty good alot of it feels little tweaks here and there, one of the biggest things vista will do is help bring x64 into the mainstream x64 in XP was a pain and its worse with linux(at least from my experience) but x64 in vista is done well.
Linux requires a bit of an investment in time and painkillers, its pretty rewarding though, but if you are joe average i dont think many would be interested i know members of my family even if i was there to walk them through it would rather spend the money and get easy to use windows.
If it scared anyone off its probably a good thing if people arent wanting to put in the time to linux then its just a pain for everyone. I love linux but im still not ready to get rid of the dual boot.