I like the TRex Active UV flood bulbs.
They are designed to last a year, and then eventhough they might still be working you should change the bulb as the UVA/B output decreases. http://www.carolinapetsupply.com/catalog/index.php?
main_page=index&cPath=44&zenid=81513b5f365c112fe1b72ad343d2a77d
Ooops, I messed up posting the links...
Here are just a few places...our local shops carry them too but they are about $80- in the stores.
I have to recommend the Power Sun mercury vapor bulbs.
They are pricey but they have the best UV output (from what I can find anyway) and provide the heat for basking as well.
I don't believe that the UV output diminishes like the tube type lights do, or at least not nearly as fast.
I have had some last 18 months or more.