Your frame helps define your space Michael. But it is often necessary to put a mat surrounding your print to separate it from the frame. I like my mats to pick up some subtle color that appears in the photo and the frame must have a complimentary color or be in keeping with the decor of the room in which it will hang. Of course I always give black and white photos a white mat. The other thing that a mat does is isolate the print from it's immediate surroundings and raw your eye into the center of the space. It might help if you have a museum near you which has an exhibit of photos to get a sense of how they deal with presentation. We here are lucky enough to have the Carnegie Museum and the famed Frick Museum near us. Their presentation of photos have helped me immensely.
Their is a growing trend to present photos printed on metal,canvas or even wood with no frame at all. that can be effective in certain instances, but I think, not always.