I got my stuff from reefgeek. They have good customer support/service, and do a good job with shipping. They also have decent prices and have a good assortment of bulbs. They carry UVL, ATI, Giesemann, GE, and maybe another brand.
On a side note, I found it useful to order a variety of bulbs so I could experiment with different configs. As a result, I have a whole mess of bulbs and you are certainly welcome to come by and see my setup sometime -- and to possibly see different bulb combos to help you decide which bulbs you feel like ordering. I have the following:
UVL Actinic Whites
UVL SuperActinics
ATI Pure actinic 03
ATI Blue plus
Giesemann Actinic plus
Giesemann AquaBlue
GE StarCoat 6500K
Depending on the bulb setup you can have a yellowish look, crisp white, blue, way blue. My current setup is probably close to a 14K look.