Another ubiquitous appliance, another potential source of large energy savings.  Here are some pointers for saving energy in the process of keeping your food fresh.

1. As with other appliances, check out the CEE Super Efficient Home Appliance Initiative’s report on Refrigerators. 
2. Side-by-side models are LESS efficient than top-and-bottom models of integrated freezer/refrigerator.  Buy a top-and-bottom model if possible.
3. Automatic ice makers and water chillers are notorious energy wasters.  They are also the most problem prone parts of refrigerators.  Avoid these features.
4. Check for the energy rating of the model(s) you are considering.  Energy Star ratings mean better, efficiency, although it is a rather ‘coarse’ measure of efficiency.  (See point 1 above for a better rating system).  If the model you are looking at does not have an energy rating tag at the appliance dealer’s store, go to another store (and let them know why you are leaving!)
5. Yes, your mom and dad are/were right.  Keeping the refrigerator door open as briefly as possible saves energy in multiple ways.  Besides the cold air flowing out and warm air flowing in (which then must be chilled by the compressor, motor, etc.) the air that flows in is generally moister than what flowed out.  That moisture itself produces an extra burden of cooling since water has such a high specific heat (measure of how much energy a substance absorbs).
6. A full refrigerator takes less energy to keep cool than an empty one.  Now, don’t go buying food you don’t need, or keeping lots of bottles of water in the frig.  But don’t buy a model larger than you will need.
7. Efficiency of modern refrigerators has improved so remarkably that if you own one over 5 years old, buying a new one will likely pay for itself in energy savings in a very short time.