I guess it would depend on what I needed to do with said equipment. Does the workflow lend itself to utilizing the iPad? Am I going to need to be frequently mobile? If so, then the combo is what I voted for, especially since the iPad can be used as a second display for the Mac.
If my workflow was not something that could make use of an iPad, or if I was always locked at the desk, then I'd probably go for the 16" MBP, since if I'm going to be limited to just the laptop's screen, may as well make it a big one.