One way to save a few bucks a year on energy is to turn off the circuit breaker for your central air conditioner during the cooler months. The compressor has a small heating unit inside (I've heard there's some lubricating oil that needs to be kept warm for optimal performance), which draws energy even in the winter months unless you turn off the power going to the A/C.
I discovered this while testing house energy use with my whole house energy monitor, and wasn't able to get the energy consumption down to zero until I tripped the A/C circuit breaker.
The heating/cooling contractor told me it doesn't hurt the A/C unit to cut off energy to it when it's not in use. An electrician suggested turning the energy back on a couple weeks before using the unit, to give it time to warm up. It's easy enough to put this on one's electronic calendar for some time in the spring. We've done this the last couple years without any problems.
As a disclaimer, I'd encourage double checking with whomever services your A/C unit before doing this.