What size pool? Seasonal or year-round? How much is it used?

In general, you will save a lot on electrical costs by going with a variable speed pump.

As a follow up if you end up deciding to go with a single speed pump you need only only big enough to pump the volume of your pool 3x every 24 hours - which most 2HP pumps could do multiple times over. This would mean a 2HP is too large. If you know the volume of your pool them this buyers guide compares the flow rates of every model of pool pump from Pentair, Hayward and Jandy based on flow rates:

Pool Pump Reviews