Well, given that you have a tank that's as tall as it is long, you're probably going to want to do CFLs, T5HOs or LEDs.
T8 and T12 light just isn't going to reach that far down into the water... Though it also does depend on the plants you intend on having. What kind are you getting? If they stick up toward the top a lot, or float at the surface, then you'd probably be fine with a regular T12 fixture.