We use electric heating--which is expensive, and while our neighborhood will be getting natural gas in the next few months, it makes no economic sense for us to replace our central heating system with gas. (The payoff exceeds the lifespan of the HVAC already installed.)
Resistive heating or a heat pump? If the former, I suspect that replacing your AC with a heat pump would save you a lot of money. I would even go so far to say that if your HVAC is old then it would make sense to upgrade (because you'd have to replace the AC eventually anyway, and the marginal cost is small), and if your HVAC is new then whoever had it replaced last time was an idiot for not upgrading to a heat pump then.