I have an older set of Logitech speakers at this point which actually draw a fair amount of power even when not playing anything, if left on. No noise, or anything. My Klipsch set on my HTPC are the same way. If you use something like a Kill-A-Watt, or a some other kind of meter to measure the power draw, you might be surprised at what many speakers draw if left on just sitting there idle.
Unplugging them is a pain though, so I use smart power strips. I have several around the house. The latest ones I've been ordering are Tripp-Lite, AV88SATG. I plug the PC into one outlet and when it turns off it kills power to the other outlets automatically. So when I turn the PC back on it turns those items back on. In the living room with the HTPC, there are times I might want the PC on, and everything else off, so I have the TV as the control. Something to look into. It costs a bit more than a standard surge protector, but they are convenient. At $30-35 they aren't horrible either.