I just threw this spreadsheet together real quick. I thought it made for some interesting info.
The electric usage doesn't seem to vary a ton. The lowest bill I've had so far puts me at 13.3 kWh a day where as the largest was actually my first month in the house before installing CFLs at 20.4 kWh. That just goes to show how much of a hog lighting is. So, power usage only varys by ~50%.
Opposite that, gas varys enormously. In summer we were using .72 therms a day with my cousin's family living with me. But, for heating in winter it jumps 763% to 5.49 therms per day.
Also, it'll be quite nice to soon have a full year of numbers to look at to compare to this year. Of course, now we'll have five less people in the house, so that should make a very large difference.