Well, I believe that a company has the right to do what they want.
Windows XP wasn't new either, since it used (heavily) code from NT.
To be honest, my timeline with windows has been 3.11, 95, 98, 2000 (for a brief period, before going back to 98), xp, vista (on a new laptop, only for the time it took me to download windows xp), and now the beta for w7.
And I think that w7 is the best thing that has happened (in windows) since xp. And that's about 7-8 years?
I have used mac os x, and linux (ubuntu, badger something? about 3 years ago). And I still prefer windows over those ones.
And about the price, well, if it exists, it's pirated. If it hasn't been pirated, it's on its way.
And yes, I agree with ArsTechnica that vista was a HUGE mistake and a SHIT operating system. But it had good ideas. And it had terrible implementation (UAC I'm looking at you).
At least, what I've seen so far about w7 has improved those flaws, and added improvements.