What kind of fish are you interested in?
You will be limited to fish that can take the cold, so that limits your options to fish such as sunfish, bass, perch, smaller catfish, and trout. The pond size will also limit your number and size of fish, so the previously mentioned fish would work good for your pond.
Personally, I like smallmouth bass since they have a lot of personality and nice coloration/patterning plus they tend to be more cold hardy than largemouth bass. You could try stocking one or two bass with a small school of sunfish such as bluegill; a small catfish such as a bullhead could also be stocked.
What are the dimensions of the pond and average summer water temperatures (or at least average summer air temperatures) so that I could give you some more specific help.