Well I am going to be the different one here and say the BC...
Why??...because we enjoy Epcot more than the MK...and we are late nighters, so we want more activities to do in the evening...
alot depends on what you guys like to do, and the park hours...
personally, our fav thing on our last evening at WDW is to do dinner in Epcot, walk around hitting the shops and having drinks while the kids make their masks...watch illuminations, and then walk out onto the BW and do the different activities there...then head back to our BWV...
depends on the park hours and if you want to see the electrical parade...which park if any would have EMH while there...also will you be going to the park for the entire day or just going for a few hours in the morning and then back to the resort for a nap before heading back again...
This would be my itnierary -
First night wouldbe DTD and then back to BC...
First morning wake up early and walk into Epcot and hit future world...then back to the hotel for a nap...then over to MK for some rides, the parade and fireworks...
Second morning would be catching an early bus to MK - have to be at the gate at least 30 min b4 the park opens...hit all the major rides before noon...then back to the hotel for a nap...wake up in the afternoon then walk into Epcot...walk around the countries...have dinner...watch illuminations...then out onto the BW for evening entertainment...
again, alot would depend on park hours and what things you guys like to see...