All the vampire metaphors in the world aren't making vampire power consumption less of a problem.
The answer, probably, is yes. Good magazine made an awesome graphic about this a while ago, showing what it might be costing you. According to one Cornell University study, you might have as many as 20 vampires lurking in your house, and your PlayStation or your plasma TV or your computer--they're only the start. That same study found that "your TV with remote control likely uses more energy during the 20 hours a day that it’s turned off and in a 'standby power' state than it does during the hours you watch the tube."
What to do about that is in dispute, between the California Energy Commission and consumer electronics companies, and their fight just got a little bit bigger.
If you're worried about vampire power sucking consumer electronics, you don't have a lot of options. You can religiously unplug everything and turn it off, but that won't work for your TiVo, which goes through a lengthy re-boot after being powered down. Investor-owned utilities like PG&E make a moderate-sized deal of recommending Energy Star appliances. But the Federal EnergyStar and EnergyGuide labels aren't required on consumer electronics. So all that useful information EnergyGuide requires, "an estimate of the product's energy consumption or energy efficiency...the highest and lowest energy consumption or efficiency estimates of similar appliance models." Optional for consumer electronics.