I recently updated my ereader to a nook color and spent a few days playing around with the stock and then updating to the latest 1.4.1 firmware from B&N. Once I found the limitations, I looked around for a way to go around them.
I ended up with a 16GB microsdhc card set to be bootable into the CM7 firmware mentioned above. A normal power up will go directly to Android where I can run what I want, have market access, and customize to my heart's desire. If I want to boot to the original nook firmware, I can, and if I want to avoid the CM7 altogether, I just take out the microsdhc card.