Hehe, yes please do not ask us guys who have to support this mess.
eskimo2, do yourself a favor. Let the bleeding edge guys wrangle with this for a bit. Initially, the OS is going to cause a significant performance dip in all games. You really do not want that.
I can see the "Texh support" forum now,...."I just installed Vista, and my frame rate sucks! Fix it!".
Me: Re-install XP and it will solve your problems. (I really wish I could say that).

Oh. here is the current pricing in U.S. dollars, for full versions/upgrades
Vista Ultimate: $399.00 / $259.00 (combines Business and Premium)
Vista Business: $299.00 / $199.00 (no Media Center, more management tools, very similar to XP Professional)
Vista Home Premium: $239.00 / $159.00 (Aero support plus Media Center)
Vista Home Basic: $199.00 / $99.00 (no Aero support)
The price is structured differently outside the U.S.