I always unplug mine. I heard that 40% of your electric bill is plugged in but not in use appliances (I kinda doubt it's that high) so I try to unplug most when they're not in use.
I was also raised by a worrying jewish aunt, so I can't run appliances (laundry, dishwasher) when I'm not home... I'm not sure exactly why, since I'm usually not near enough in the home to see if they explode, I just know that I CAN'T physically walk out of the house with things on... I've tried :shock: