We live fairly nearby, so we can go and come as we please. Therefore, ALL of our trips are Sunday-Thursday.
To some extent, your choices may depend on whether you will have a car or not. If you don't have a car, your only real decision is whether you REALLY want to do something else or not.
If you want a strictly Disney trip, then stay somewhere onsite. The choice really only depends on the type of lodging you want -- choose deluxe, mod, or value, depending.
If have a car but don't want a strictly Disney trip, there are several options. One is to stay in the immediate Orlando area and hit US/Sea World/etc.
Frankly, my choice would be to explore some of Florida away from the Disney area.
For example, a trip to St. Augustine (oldest city in America, founded 1565 -- 42 years before Jamestown and 55 years before the Pilgrims), and then Kennedy Space Center on the East Coast. (With the optional stop at Daytona for NASCAR fans).
Or, on the West Coast, Sarasota/Longboat Key or Sanibel/Ft. Myers.
For pirates, Key West. For supermodels, South Beach.
For people who enjoy more natural settings (and I am NOT making this up!) --
Miami with visits to John Pennekamp Coral Reef State Park, Biscayne National Park, Everglades National Park

banana: ), Big Cypress National Preserve and about a dozen other places.