Water Heaters: Tankless Vs. Tanks.

A good article from Builder Online on tankless vs. tank costs.

It doesn't address the fact that many people take longer showers and don't save as much, and that's not a great idea if you're on a septic system.

It does not address solar water heating. Solar water heating takes up more space and has some fairly high retrofit costs, but most saves money immediately if installed at construction.

Here's a link to an inexpensive $1000 system.