Where the heck is Shawn (real80sman) when you need him?
My understanding is that you can get a heat-pump that runs on either electricity or gas. I'm a big fan of gas, myself, but I suppose it depends upon the energy pricing structure in your area.
Ditto Michael's comment on the cover. That's a big deal.
When I was younger, a friend of mine had a pool with a hybrid solar/gas system. That was really cool.