SO!
I went with a corner aquarium. It's 36" on each side and 30" high (pentagon). It's got 7 chambers in the back. The back corner is where the powerhead is, and has bioballs on either side. The other four chambers are on the outside of those ones and only have pads in them.
Filtration:
I'm thinking about putting a bag of Bio Chem Zorb in each of the four chambers.
I have "drip trays?" on top of the bio balls. What are these for? Someone told me to make sure they're slanted. Why?
Is it really worth putting in two 150w heaters for efficiency, or should I use only one?
Lighting:
I was thinking of going with a HO T5 4x52w fixture, per Byron's plant tank walkthrough. If I use two actinic and two 10ks, will the white light wash out the blue of the actinics?
Substrate:
I plan on using black Eco-Complete. How much of it will I need to get a 3" bed? I'm sure you'll need more info to help me figure this out.
Any other advice? Freshwater, of course. I'll move on to Salt when I do my 300gal =)