If you plan on spending the most time at MK on a monorail resort-Contemporary Resort, Polynesian Resort or Grand Floridian. Contemporary is within walking distance to Magic Kingdom.
If you plan on spending the most time at Epcot-an Epcot Resort-Beach Club, Yacht Club, etc.
I think Animal Kingdom would be fun but, it is a very long way from the other parks so, take that into consideration if you are contemplating that one!