a few more ideas to add in here:
1. get a home energy audit (it's worth the investment): http://planetsave.com/2010/10/19/going-green-tip-8-get-a-home-energy-audit/
2. cut the air conditioning. some tips on that: http://planetsave.com/2010/09/20/going-green-tip-7-cut-the-air-conditioning/
3. shopping is not part of your home energy or water usage, but if you are looking to do your part in some simple ways, watch what you buy & who you buy it from. climate counts has an excellent campaign going on to help you out with that: http://planetsave.com/2010/12/08/climate-counts-striding-shoppers-campaign/
if more come to mind, will let you know 








