Well, I MIGHT plant...but I probably really shouldn't. There will be some massive, not so friendly/gentle fish going in there.
I think i'll pass on the metal halides, I can get 1.7wpg with 2 standard 48" fixtures (with 4-65 watt lamps each), and come up to $432 instead of $1,500. I don't think I would even NEARLY need the 4.6wpg provided by the metal halide fixtures....even if I do atempt to plant it, it won't be with any high light plants.
rallysman, you have a 505g tank!?! That's really, extremely large. Love the avatar by the way...but it needs more cowbell.
It'll be a couple months before I have the foundation ready for the tank (have to rip up the floor, por concrete foundation, etc.), but i'll let you know how I like it rayman. Though I think the answer is already very obvious...
-Fish?