Thanks for the input guys, I appreciate it. At this point, I'm trying to economize my plans, at least until I get my feet wet. So a lot of the questions I'm asking here are attempts to establish a kind of mental graph of "rules of diminishing gains" given the amount of space I have available, the amount of money I'm willing to spend, and the amount I'm hoping to grow. Those factors can wiggle a little bit, but not too much, depending on what I stand to gain, of course.

Given that the most elaborate I'm going to get C02 wise is one of those "microbe buckets" you see advertised in the magazines (or if I can find some kind of home-made alternative that works about as well or better), and I don't want to spend too much on air conditioning, fans, etc. 600w is probably going to be the most I'll invest in light wise, up front.

At the same time, I am willing to spend some coin on this - it's not like I'm looking to go totally "cheap and dirty". So, once again, it's within all of those qualifications that I'm looking to strike the best balance ("best" ultimately being judged on the criteria of yield quality, yield quantity, and how little of a headache the specific garden set-up causes me.)