Wow, what a most painful process. I finally have "Android Composite ADB Interface" displayed under "Android Phone" and the serial number displays with the "adb devices" command.
I went through the adb setup a few times, and did not realize that I needed "USB debugging" selected from the NookColor Tools > All Settings > Development. It was also frustrating to see "Nook Color" pop up in the Windows Device Manager during the device driver install, only to disappear.
Even then, I still had problems. I finally disabled "Auto Mount", and toggled "USB debugging". Uninstalled the drivers a final time, and Windows this time prompted me to search for a driver, instead of charging ahead and installing drivers that only resulted in the "USB Mass Storage Device" and two associated "B&N Ebook Disk USB Device" listings.
Now why was I trying to install adb again?