I've said it before, and I'll say it again. No matter what OS you use, you are bound to run into driver problems if you don't do your homework before hand. I know it is tedious, but it will save you from hassles like those. If you have existing hardware and you want to change your OS, you need to do your homework again before you even bother installing the new OS. If you can't find information about drivers for that OS, you are taking a risk installing it anyways and your results will never be guaranteed. If someone were to ask me to build them a new (windows based) computer, I would still build them to spec for Windows XP x64 edition. It is still the best performing windows platform for an average gamer.
It is very likely that any hardware supported by XP x64 will be supported under Windows 7 in the future. I let them know this before-hand, but also include the standard "no guarantees" caveat. I am not a fortune teller, but there is a bit of logic in thinking that any vendor providing 64-bit drivers for Windows XP will be on the bandwagon for Windows 7--unless the hardware is particularly old. At that point, you need to ask yourself why you are buying old hardware for a new system.
XP x64 is very stable and very fast if you keep this in mind, and I have more than a few friends who will vouch for that. As always, your experience may vary, but yeah, drivers can really, really, suck and I feel your pain there.