Wow! What are your electric rates? My bill includes water and sewer and the electric is now pushing $0.15/kwh but I barely broke $500 for a two month rate for the total a few years back, even with my old SEER 10 system in a hotter climate. The new unit I have now is looking good though because it is knocking electrical down by a 1/3 and is more comfortable as well. Global warming will make it pay out rapidly since the old unit was finished anyway, and the upgrade was only negligibly more than the cheapest option (hmmm, it is probably already paid for as of last month.)
Hit 105 today (and I ran my 5K route in it...at a recent personal best time). Tomorrow the prediction is up to 110 F--time to do some swimming instead. Local weatherman who usually nails the trends and long range forecasts suspects we will break the local all time record of 113 F in the next week.