I also lean towards the original card number, although my reasoning is that it would be more logical to filter for that card number when searching for the cards in the database.
Of course, that opens up the can of worms regarding NNOs when some sort of number is present, and I know how Billy feels about that one
I'll never quit collecting entirely, but I am downsizing. Check out my COMC store and help me thin out what I don't want so I can buy cards that I do want. See something you like? Send me a message on here, and we can knock the price down quite a bit. I'll even take a bit of a loss if it means getting you a card you really want.