For a home based, personnal use, less-than-ten-years-old computer this is a non issue - at least with seven x64. It detects pretty much everything by itself, and if not you can use the vista x64 drivers.
Sure you can find hardware with no x64 drivers whatsoever and I'm certain someone is going to reply to tell me how wrong I am because his 5 years old serial port thing which barely made it in 32 bit stop him from upgrading, but for joe user bying a new computer installing windows x64 would be painless*.
I think they will have way more trouble understanding what is that UAC thing is and "what the hell is a standard account anyway".
* actually and to be honest, that wouldn't be entirely painless thanks to the absurd number of softwares who require to install some kind of shell extension yet forget to provide a 64 bit version. But hey at least that's not a driver issue !