I thought, being all electric, your winter usage would be much higher. I'm guessing you are doing much of your heating load with wood. Depending on family size, your summer usage might be considered pretty normal. I'll bet, though, if you got anal with a kill-a-watt meter, you could cut it down by at least 25%. I was able to knock mine down by 30% a few years ago. One of the main culprits was the dehumidifier in the cellar. It was using a lot of electricity to do very little. I replaced it with one that worked. I also did some air sealing down there, which helps keep the humidity out.
I bet a GSHP (geothermal) would work well where you are. It could do most of your hot water as well. It might be hard to justify the cost where you are, considering the cheap electricity and firewood. Maybe though, over the long term, especially if you wanted, or needed to move away from wood, it might be worth looking at.