How common are 64-bit workstation operating systems today?

I noticed from Windows Vista team blog today, that Microsoft is finally seeing the adoption rate of Windows XP/Vista 64-bit raising fast. Yes, both these OS versions have been here for a long time, but it seems from the blog post that the turning point is approaching fast.

Well, the general public might continue to use 32-bit OS versions for a long time, but when 64-bit versions get more common, the driver issue will be a thing of the past. For example, I've checked my peripherals, and almost everyone (except my EOS camera) have 64-bit drivers, from sound cards to printers.