The reason for only one version & pack of MacOS X is that it runs only on a few selected hardware, & U will need to buy a Mac to run it, thats why it costs $130, they are already making money by saling the drivers & hardware
Windows Vista on the other hand, install on millions of possible hardware configurations, not sticking or limited to just one. Besides, not everyone needs MCE features, or Volume shadow copy, or server support, so why give them these components? Why not just relese a slim version at lower cost, & if the user requires he can Express upgrade to other higher versions or use 3Rd party Alternatives like for example, media portal, or SageTV.
Whats the point of giving someone Home premium, when he doesn't have hardware enough to run it ( a DX9 based gfx card), why not give him an option of Vista home basic at low price
Besides, MS cannot make just one edition, like Windows Vista , they will again get sued for relesing one with WMP11, or one with Inbuilt WLM 8.1. Vista targets a lot bigger market, & users can buy whatever they want.