The October 2007 issue of Consumer Reports has an article on saving money in energy costs. Among the usual--Add insulation, reset your thermostat and hot water heater, and change your lights--is a new one to me. When you keep your house cooler, you can use a portable heater in just one room for supplemental heating. However an open floor plan can make sealing off one room almost impossible. (Be sure to read the article on space heaters for more information on temperature control--get a heater with a thermostat--and safety.)
Compact fluorescent lightbulbs (CFLs) will save you money, BUT they contain mercury. You have to recycle them, AND you must be careful not to break them. The magazine has a sidebar on what to do if you break one. First, open the windows and leave the room for at least 15 minutes. Then clean it up carefully. (The sidebar has instructions. Hopefully they're online somewhere.)
Consumer Reports also has interesting articles on credit cards, sweeteners, vaccuums (it's really hard changing the bag on one vaccuum!), cars, and the new cordless phones. I have to get one of those! There's a good piece on cleaning stainless steel refrigerators (watch out for mustard!) and a warning about a popular product for men.