Lighting?

The only space I have is a 40x40x40 in cube. I want to split it off into two sections(a flowering and a veg/clone space). I have so many ways of doing this, but I need a good start. I want to know what should I use for lights in such a small space. HPS, metal halide, or cfl. venting this area shouldn't be such a problem... After some good advice with lighting I should be able to design the rest.

I included a pic of the area.(The shelf is in there to show scale of space)

you would need ALOT of cfls to cover plants in that room. i'd try the M/H in your veg room, and the HPS in your flower..... when purchasing, make sure you find out what the "footprint" the specific light gives. as in, how many sq.feet will that particular light will cover. that'll ensure optimal lighting on either side. good luck

So I figure I am going to make the flowering room 25 x 40. I remember reading that to measure how much lumens i need to use this formula L x W / 12^2=X(5000Lumens) My calculations would be (25 x 40)/12^2=6.95(5000) so the total amount of lumens would 34,750 lumens. Am I correct? If so where would i purchase a HPS light that is close to that. A 400watt is over kill I think because it would create more heat then I would really want. Advise would help.