I always stop at red lights* but will slow and roll through stop signs if safe to do so. BTW...The Delaware legislature has just passed a new Delaware Safe Bicycle law which the governor will imminently sign which allows rolling through stop signs among other things.
I believe that stopping at reds gives the bike community credibility and more respect from motorists.
* I admit that when I'm in really rural areas with long flat sightlines, I'll stop and then proceed if no cars are in sight