Just for the sake of saying something about running on lower pressures being okay... I run 700x25C at about 110 psi. I'm big, too - 5'11", 275 pounds. I haven't had a pinch flat since I hit a raised metal drain edge at 20 MPH, but I had a whole bunch of them shortly before I came to understand that the higher the pressure the faster the air bleeds out. For me that means checking the tires every time I want to ride.