I'm in my last week here at Cooperstown/Oneonta and there was only one other place I have eaten that merits mentioning. Based on the recommendation by Roy of Plain Gray Swatch, I had my first Oneonta pizza at Cosmos Pizza. Great pizza, easily the best I've had up here and one that would that be delicious anywhere.
The place is a bit hard to find from Main Street. There is a doorway that sends you down a flight of dingy stairs where you expect to find a 1920's speakeasy. Not surprisingly, there is a bar at the bottom of the stairs but Cosmos is also there. And unlike many pizza joints where you have actual Italians working, the two fellow working there that evening were bespectacled younger guys, definitely Anglo-Saxon in heritage. They make good pizza, though.
Thanks, Roy, for the recommendation and folks, if you're up this way to visit the Hall of Fame or some other reason, I don't think there is any reason to eat in Cooperstown. Use your money a little more wisely and make the twenty minute ride into Oneonta.