Hey Trepie,
Well, I'm not sure if you actually can buy the card separately (ie. not already installed in a new computer) but don't get the GeForce Go series. Apparently, there's a conspiracy going on, and in order to get the drivers updated, you have to go to the computer manufacturer instead of Nvidia themselves.
At this juncture I would definitely go with an ATI card.
Also, here is a
FAQ about cards on the BBS.
However, I will add that I have a Go Series card running Vista, and thank GOD have NOT experienced any problems (there was a BSOD once, but I'm pretty sure it's unrelated, as I can't reproduce it).
Hope that helps a little!