hi,
Lots of idea's there, I don't 'own' any fish, so I wouldn't have a clue
But hey, for a medium tank like that...LED's and ccfl's would do but both emit quite a lot of light for a small area. You could get a semi transparent perspex tubes and bung some leds on the ends. Diffuse soft light, which will be more than enough to light the aquarium without pissing the fishes off too much, or blinding you when the lights are off. I tihnk the ones from pet shops generally are quite dim, perfect for your app. Btw, I've done the above before to make a 'cheap' floresant tube, only used 10 led's and was quite bright (thanks to epoxy and efficient light extraction)
If you do go down the LED route, remember, 'high brightness' usually means narrow viewing angle, I'm not sure what the angle is for the luxeons but I reckon anything above 100 degrees would do. Else...you'll have to difuse them your self (cheap plastic tube + baking paper or something semi transparent like a plastic bag). That is unless you want uber bright spot lights?
As for ccfl's, they do require 'special driving circuitry', but you wouldn't need to design one. Theres plenty of 'inverters' about, ebay has loads for TFT monitors...although they are quite powerful, and then of course you need to water proof the tube connections/inverter if its going anywhere near water, don't know what 1-2Kv would do to you fish....also, the ccfl tubes for the monitors themselves are on there for a few £ (or $) these are damn bright though, and not very long. Although....two at the top of the tank, shining into some plastic strips (try the rough acrylic, like sandblasted or 'diffuse') that will shine soft light down into the tank.
Anyways, as you can see, I'm biased towards led's. They're not as efficient as ccfl's but easier to work with (power/drive) and they CAN be diffused quite well given some acrylic/plexi, sandpaper and some determination.
Blueteeth.