Clean install is always better, period.
Whether your stuff works right off the bat or not is irrelevant. If it can work via upgrade, it can work without the upgrade as well, you'd just have to install it correctly (Which in some cases, may mean a direct driver install from device manager).
The only advantage to upgrading is not having to reinstall programs or move any files, and frankly that's not much of a reason anymore with the speed of PCs and their backup drives.
I've done both. An upgrade over Vista SP1, and a clean install over a freshly re-formatted drive.
Fresh install wins by a landslide.
Run the 64 Bit version here and loving it!!!!If you have a dual core machine or better and are going to do a clean install you might as well take the plunge now and install the 64-bit version since you may not have the opportunity otherwise.