I don't own a house yet, so there are certain improvements I'd like to make, but can't. This is one of those improvements. My friends Dean and Carey recently installed a tankless water heating system at their house. I'm posting a picture here so you can oogle over it too!

Energy efficient. Instead of constantly maintaining a tank full of hot water, this unit heats water on demand.

Here are a few sites with more information on tankless systems:
http://www.tankless-water-heater.com/
http://www.itankless.com/
http://store.irawoodinc.com/tawahe.html