From the posts so far, COSTCO is the favorite mostly on price. After that it's a bit of a wash with Shell possibly edging out the others slightly.
Shell users seem to want V-Power.
Top Tier fuels are important to more drivers than I would have thought.
The appearance, maintenance, busyness and amenities of a particular gas station are a significant factor to many.
Pay at the pump, rewards programs and the like don't seem to be very significant in choosing a brand. Perhaps this would be different if there were more ladies participating in this survey.