I'm a little confused. I just bought a laptop running Windows 7 64-bit. I plugged my Droid into the USB and enabled USB tethering on the phone. It seems to make the "Network and Sharing Center" in Windows 7 hang. I tried downloading and installing the latest drivers from Motorola. Same thing.
Everything I'm seeing from Google searches is that it just works. I must be missing something.
BTW, I have the grandfathered unlimited data plan that I carried over from my OG Droid if that makes any difference.