I get asked all the time about tankless water heaters. Tankless water heaters have come along way in the past few years that may make it the right item for you. While it is not right for every situation, it could be right for you. They can be installed with natural gas or propane.
Do not wait until your hot water tank is leaking to ask about a tankless water heater.
At this time I will not recommend a whole house electric tankless water heater. However a natural gas or propane tankless water heater is recommended if you want an endless supply of hot water.