Get the 4x Tek light and suspend it with the cable hanger. The best part is moving the lamp up and out of the way when needed, besides looking bad ass. I did go ahead and suspend mine from the living room ceiling. To me it looks cleaner than having a frame suspending the light over the tank.
All depends on your needs there are endless options.
These guys have a good selection and looks like they are providing GE bulbs right now for the 6500K range.
Specialty Lighting at Specialty-Lights: Professional Lighting, Facilities Lighting, Specialty Light, Unique Lighting Systems
I picked up mine a couple of years ago from them, good folks.
What kept me from going PC was every fixture used fans to keep cool. Fans = Noise. However little it's still white noise I can do without.
Aside from the Tek going through it's heat cycle it's silent.
Sounds like a set of headers cooling down after some hard running.
What ever you do go topless.
Looking back on that tank you may want to look at HQI since you are on the tall side of things. There are fixtures that have two T5 and two HQI in them. Problem is once you go that route it's big money as your probably aware.
Peace,
Sean