Canon just released Vista compatible 32-bit and 64-bit drivers for my CanoScan 4200F scanner. The old 32-bit drivers didn't work on Vista (and there were no 64-bit drivers available previously). What's also good, is that the 64-bit drivers also work fine on Windows XP x64 Edition :-)

The drivers are available from the American Canon website (they aren't up on the European site at the moment).