Most folks serious into plants have more invested in lighting than in the tank itself. I'll have close to that and thats buying my 240G brand new. Take a look at some of the combo metal halide / PC fixtures, there are many in the $600-800 range. Tek lights are quite popular, for a well equiped 6 bulb unit I think your lookin at almost $400. AHSupply is practically dirt cheap.
But for your plant choices you should be fine with a lower light setup. All depends on what you want.
I paid ~$60 for my 36w fixture & bulb (inc shipping) from ahsupply.com. I paid $10 for the tank it's going over. Still have to invest a little more tomorrow to build the hood.
When you see one of the reflectors in person you realize why they put out so much more light than most. VERY shiny and multiple angles.