First question would be where will you be that day.
We always enjoy a nice lunch at Kona Cafe if we are at Magic Kingdom, it' a nice break in the day or the Grand Floridian Cafe at the Grand Floridian.
If you are in Epcot that day, I would pick a country that interests you and go for that.
If you are in Hollywood Studio's we really like Mama Melrose's or if you don't do a full day there, a late lunch somewhere in DTD is good, I would recommend Wolfgang Puck Express.
If you are at Animal Kingdom, we really, really enjoy Yak and Yeti.
If you are on a break day, I highly recommend picking a resort you have never been to and eating there. It's always fun to go exploring.
Enjoy your trip.