Yes, you need a good
UVB bulb and a basking light. The basking light can be just about any bright, white, hot bulb. The UVB tubes should not be a coil (and really should be a ReptiSUN 10.0).
But, yes, there are Mercury Vapor Bulbs, too. Confusing huh? MVB's produce UVB and heat from one bulb (IMO, the best way to go).
The tubes need to be replaced every 6 months and the MVB's should be replaced every 12 months, minimum on both.
The UVB is important for them to metabolize calcium (I think the D3 helps with that; just like in humans, we need D to absorb calcium).
But that leads to another point: Calcium. If you use a florescent tube, you should supplement with calcium plus D3, and if you use a MVB, you should supplement with calcium without D3. MVB's are so much like the real sun, that they actually stimulate D3 production!
Good luck!