For me, it depends on a few factors - how crowded the con floor is, how big my group is, any large props that make maneuvering difficult, and how popular the costumes are.
For example, at the last con I went to, I cosplayed as the Sniper from Team Fortress 2 on Saturday with another friend as the Pyro, and my husband as the Heavy. It was the busiest day, and we met up with another group of friends who were also in TF2 costumes (and picked up strangers!) - at one point, our group was 12 people, some of whom had very large guns. At that point, it just made more sense to find a corner and let people come to us for pictures - we ended up staying in the same spot for a couple of hours, posing for photos. When we broke up for lunch, it wasn't too hard to maneuver 2-3 people through the crowd, though we still got stopped for photos a lot.
Generally, I figure if you're going to be blocking traffic for long periods of time (large group, large costume/prop), it's best to try to find someplace out of the way. Judge it based on how things are going - if it's super busy and your costume is popular enough that you're standing in the aisle for photos for more than a few moments at a time, be courteous and get out of peoples' way if you can. If it's not too busy and there's still room for people to pass by when you stop for photos, by all means keep roaming.
Oh and also be aware that it's completely okay to (politely) so no if someone asks for a photo and you can't (on your way somewhere), or don't want to (hungry, tired, any reason!).