Most of the hardware was supported without any issues. NVidia, Creative, Asus had fully supported drivers and the hardware worked fine after installation. But, there are problems with other hardware on Vista 64-bit. Vendors seem to be scared to provide 64-bit support on their devices.
Kensington 33348 Bluetooth USB 2.0 Dongle - No Vista 64-bit Support Yet.
Diamond XtremeTV PVR660 USB 2.0 - No Vista 64-bit Support Yet.
Other Vendors are slowly catching up with their drivers and software.
Sony Ericsson will be releasing software updates in Q2 2007.
Oh well, I guess these are the "joys" of upgrading to a new Operating System.