Everyone wants to save money, in both the short term and the long term. One of the best ways to save money -- and hastle -- in the long run is to replace old utility units, which were built in a time when electricity was cheap and manufactuerers were more concerned with power than efficiency. New units consume up to a third of the electricity as old ones, and some units are especially designed to save energy, and the expense of being more expensive or taking more time to do their job. It is, of course, always possible to do your laundry by hand, or use cold water in the washer or when showering, but most people find this inconvenience to be uncomfortable. These things are impractical to the point of pain where the winters are long and cold.
Water heaters are the same, and new units almost always outperform old. Smaller units generally cost less money, and some use fancy tricks to achieve a slightly higher energy performance. In many ways, heating technology has not dramatically changed; a gas heater, for example, still applies a flame to a metal grid, which carries the heat into the tank. That said, modern units are still a bit more efficient, and are at least better insulated, so less money evaporates as thermal radiation. There is still such a thing as a high efficiency gas water heater; go shopping and compare stats with what you already have.
One high efficiency water heater is the tankless, or on-demand hot water. These things are costly to install, but can save money in a variety of ways. Since there is no tank, there is no tank of water to constantly keep warm. If hot water is only used a few times a day, or especially only a few times a weeks, then significant savings on energy can be achieved. They heat only the water you use, and can provide unlimited hot water if needed. There is no fluctuation in water temperature, as is with a tank, and it does not deliver excessively hot water unless specified to. Temperature is controlled.
The most energy efficient water heater is solar, but this means installing solar pannels on your roof. The energy comes from the sun, but this may be unreliable if you live where it is mostly cloudy, or if there is too much tree canopy.