Well Vista with a 128MB DX9 card is fine, as far as load is concerned, the Aero Hardware Acceleration is there to take the load of the CPU and look pretty.
Now as far as versions are concerned, the Vista Home basic laptops that are out are not great, I think that home basic was a poor idea, as hardware gets better we are still keeping manufacturers lazy by not getting them to move to more powerful hardware acceleration. I always get calls from people who cant watch HD videos on their "new" laptop because they were not informed that they should have hardware GPU stuff to work.
The studio install problem was to do with UAC. Turned it off :)
Performance in games in fine, as good as it was on XP, need to see what the new Vista games are like , I have flight sim X, still need to install it though.