Try reading the forums at DriverHeaven. They keep track of all the latest drivers and you can be sure someone is going to post problems with them.
Its going to be an issue for awhile. I mean, they still sell 8MB PCI cards on the shelf at CompUsa, and for as long as I can remember the "latest" drivers wouldnt hurt you, even if they didnt help you. The advice has ALWAYS been to get the latest driver. Apparently with the new generation of video cards, thats not true anymore, becuase ATI has the same problem. Their newest drivers have issues with the 9xxx cards. As long as they crank out the new cards, and esp. as PCIx begins to replace AGP, the "last gen." cards are going to get cheaper and cheaper, and more and more people will see them as viable "in between" upgrades. And download the newest drivers for them, not knowing to do any different.
And you're right, both companies should come out (IMO) and let folks know, "Hey, you dont need this one if you have an older card, use this driver". I'm sure they dont want to make direct comparisons that would hurt the sales of the older cards though.