Amongst my collection of hardware I've got one pc with 64 and one with 32. They're both newer hardware so I've not had any real driver issues. Overall the industry has yet to adopt 64-bit with stellar enthusiasm IMHO. Especially for already released products. But due to the 32 compatibility built in, I've yet to experience a 32 app that won't run on the 64 platform.
There's tons of debate on tech forums with specifics on RAM utilization, execution times, and basically anything you'd ever want to know. Grab some coffee, Google windows x64 and have a ball.