I suggest imaging the old installation, and plugging the drive directly into the new system. If you're lucky, it will detect all of the new hardware and install the appropriate drivers. (Windows 7 appears to be much more complete in its included drivers than Vista was.)
The clean install is still safest. I got to be fairly efficient at it while I was messing around during the Windows 7 beta period. (Leaked build of the week, that sort of thing.)