I'm a little new with heat sources, so you might want to wait until someone corrects me, but from what I've gathered, ReptiSun tube and coils don't give off heat, just UVB. Mecury Vapor Bulbs give off good heat, I've heard, but I'm not sure if that should be used with the ReptiSun tube. I use a basking bulb for my heat, but they need to be monitered closely as when the start to get old, they give off less and less heat. Also, from what I've gleaned from the forums, you shouldn't be using a colored bulb, but don't quote me on that.
for heat you have two choices. 1) use a household bulb in a wattage that gives off the heat your tank needs. or you can use the hallogen flood light bulbs. They give off more heat than the regular house light bulbs do. If you go this way you need an additional bulb for uvb. Do NOT use any coil or compact uvb. The best fluorescent uvb you can get is the reptisun 10, tube. (again, NOT coil).
2) you can use a mercury vapor bulb, one of these: the Mega Ray and the T-rex. There is one other I can't remember the name at the moment. If you go this way, most of the time you don't need an addtional heat bulb. Some times you might not get as much heat as you need and might need, say, a 40 watt bulb.