I am not 100% sure who will win, but I am pretty sure that whoever wins will do so by double digits. If the Saints offense gets going, they are nearly impossible to stop and could put up 45-50 points. If the Colts offense gets going, they also are rather difficult to stop...and their defense usually rides that momentum and pulls out a few stops to allow them to build an insurmountable lead.
I think that the Colts will win, but...stranger things have happened. I am nearly certain that the margin of victory will be double digits, though.