I use a 100 watt red heat-lamp. I've got a probe-thermometer sitting above Khalil's warm-den to measure the temperature on the ground, although it hovers around 85 for now, it'll get warmer as summer reemerges.
UTH and heat cables. Lauren and I are afraid of heat tape because a) we don't know what we're doing with the wiring and b) we've heard horror stories about how heat tape has tendencies to malfunction. So you put a and b together, and you get a real bad idea. Heat cables work just fine for us.
Three UTH's and two lights, the heating light usally does a good job of heating up their rock hide that they like to lay on so they get belly heat and basking heat