I found this on Consumer Reports and am now wondering if it would be worth my while to convert to gas instead:
"Look for a long warranty. Most cover 6, 9, or 12 years. Heaters with the lowest and highest warranties differ by just $60 to $80 for electric models and $50 to $100 for gas units. But we found much bigger differences inside.
Electric water heaters with 9- and 12-year warranties typically had larger heating elements, thicker insulation, and thicker or longer corrosion-fighting metal rods, referred to as anodes.
Most higher-warranty gas heaters had bigger burners and better heat transfer for faster water heating, along with more anode material and thicker insulation. An exception: Whirlpool’s 40-gallon gas heaters, whose 9- and 12-year models are identical inside.
Consider gas. Based on national average fuel costs, gas heaters cost roughly half as much to run as electric models and can pay for their higher up-front cost in as little as a year. Factor in the cost of running a gas line to your home if you don’t have one. Also consider adding insulation to hot-water pipes and the cold water pipe exiting the water heater.
Tankless water heaters save energy by heating only the water you draw. Many factors will dictate the energy savings including how much and how often you use hot water. However, our recent tests of tankless water heaters show that while they are more energy-efficient than conventional water heaters, they are not necessarily more economical over the long run."
(Consumer Reports Nov. 2007)