I episode I saw was about whether it was more cost effective to leave the lights on for two minutes when you left the room, or leave them on. The myth was that it took 2 minutes of energy to turn on the bulb. This was proved as false with a bunch of high tech meters. Basically, the worst bulb they tested, took 2 seconds worthg of power to come on, so only if you left the room for less than 2 seconds was it worth it.
Less wattage means less power, means cost savings. Standard light bulbs really do not amount to much of your electric bill. Appliances and HVAC is where it is. To save $$ in the summer, run your dryer only first thing in the morning. Remember, you must draw in outside air to replace the air it is blowing out. Would you rather suck in 70 degree air in the AM, or 90 degree air later in the day. Do the opposite come winter, run your dryer when it is warmest out. Turn your AC up 1-2 degrees and use a ceiling fan to keep cool. Make sure you have good attic ventilation, as standard shingles hold heat for almost 6 hours after the sun goes down.
http://moneycentral.msn.com/content/Savinganddebt/Finddealsonline/P42610.asp http://www.energy.gov/yourhome.htm