I've never been able to get my Motorola Droid (first gen) to connect over ADB in Windows 8, even with all the above set. Other devices in Windows 8 64-bit work with those settings. Not my original Motorola Droid though.
But ADB works for me in Windows 7 64-bit, once all the above settings are also made. I think the modern ADB USB driver for Windows 8 only half supports devices as old as the original Droid. It's quite frustrating, but I don't know of any other way around this for now.