I think having a list of photos near me would be great! Possibly have the popular tab have a "near me" sorting order or just a "show near me rather than popular" view would be awesome to discover cool shots in your area.
Without question, this would be great. Much like the Twitter feature that allows you to see Tweets near you. I'd love to see the photos taken near and/or around me and compare them to what I'm doing/seeing.