I enjoyed the article comparing the efficiency of different kinds of lighting but would be curious to see one addition: Metal Halide.
It's my understanding that they produce far more lumens per watt than anything else. Although they produce a LOT of lumens and use a lot of watts and take forever to come on, especially if they're still hot from being turned off recently. So they're not useful for in-house lighting.
I use 3 400-watt ones and 8 250's (3.2Kw total) in my 7200 sq ft workshop and there's so much light I almost need shades.
An unscientific comparison tells me they're much brighter per watt. In my 1200 sq ft garage (with 12 foot walls -- the workshop has 16 foot walls) I've got 24 F40T12's (by my reckoning, about 1Kw of draw) and the brightness in the big building seems much greater than in the smaller one. 3.2Kw of juice to light 6 times as much floor area (more brightly) as it's taking 960 watts to light in the smaller building. Assuming the same brightness in both buildings, the fluorescents in the smaller building are using .8 watts per foot and the metal halids are using.44 watts per foot in the bigger building. Hope I'm doing my math right. Those numbers look surprisingly small.
After reading the article, I'm going to replace the garage's F40's with T8's, perhaps of lower wattage, since the building is only used for parking cars, and separate the lights onto two circuits/switches so I can just have a few of them running full-time and fire up the rest only when I'm working in there.
Anyway, I'd be curious to see someone who knows what they're talking about (I'm a relative newbie but will post later about some of the many AE projects I've got happening and in the works) do and apples/apples comparison of metal halide vs fluorescent for those of us who need to light large areas.