http://computershopper.com/roundups/200609_microsoft_windows_vista_unveiled_1
click on next page on bottom right-couple of pages long :
Windows Vista Ultimate seems like the one most people will want, how much will it cost 
As is usual, cost will be too much until it has become old and a new OS is almost out. 
every release of Mac OS X is $129 and there are no 5-10 diffrent editions
From a friend of mine that has installed Vista Beta. He stated this:
“the size of the windows install. It’s just over 7 Gigabytes, I can just imagine the problems finding out why a program doesn’t work, with all of that coding.”
7GB is very large compared to XP but then Hard drives have grown too