UTH's and flexwatt are the best heating options for most snakes because they are terrestrial and get their heat from below (sunning on asphalt or rocks is more about absorbing the rock heat than the sun).

However, many of us who cannot afford to keep the room our snakes live in at 80 use lights as supplemental heat. As long as the lamp is at least 8" above the cage top, the heat won't be too high and it won't kill your humidity.