$79? No way. As I said, I wouldnt even put in a $20 one if I had to buy it. Heck, I wouldnt even put it in the incubator either, I would wire it outside. I mearly mentioned the power supply because in this thread and others, people mentioned having trouble finding a sutable wall wort for powing the fan and around here old PCs are always available to scavenge parts out of (power supplies included).
It was my understanding that building one of these was a way to get a bigger incubator for a much cheaper price then even the smallest comercial ones. If thats the case, I certainly understand why you wouldnt use a expensive server power supply, much less a cheaper off the shelf PC supply. If you lived closer to me and gave me a weeks notise, I could give you a box full of used but working ones for free.
Rich