Nothing non-stop MCI-RDU. Connecting you're served by AA (ORD, DFW, LGA), NW (MEM, MSP), DL (ATL, CVG), CO (EWR, CLE), UA (ORD), and Airtran (ATL).

You've got a honeymoon to finance with miles, so I'd base the decision on where you want to go on the honeymoon.

Airtran easy to eliminate due to no international network.
I'd eliminate UA due to uncertain future.

That leaves CO/NW, AA and DL.

My preference is AA. DL as a close second. I'm not a huge CO fan.

AA has a great network in oneWorld, good departure times out of MCI for RDU (DFW, ORD, LGA) and you can Gold/Plat challenge for status once you start flying.