OK, In this troubled economy, I'm going to try to reduce my costs. The first step is to find out what size generator I can get away with. I can save $5,500 on the cost of the generator by switching from a 30Kw water cooled to a 20kw air cooled.
I found a generator forum on the Internet, and this product was recommended to monitor the power consumption of the house:
http://www.theenergydetective.com/what/overview.html
This will give me a good idea of how much energy I use on a daily basis (of course I'm not running the air conditioners in the winter). Also, if I do install a smaller generator, it will let me see how close I am to an over-load condition.