What everyone overlooks are "Wall warts" These are Death by a Thousand Cuts. They are supplied with all of your gadgets, and sit there getting warm dissipating anywhere from 1-10 watts each, even when the device they are powering is off. The gadget manufacturer has no interest in making wall warts energy efficient; it just drives up their costs. Even though there are standards for Standby power consumption, they are not mandated.
Wall warts come in 3 flavors. AC (transformer only), linear DC (regulated and unregulated), and regulated switching DC. The first two use iron core transformers at mains frequency (50 or 60 Hz). The ones with iron core transformers are built with as little iron as possible as it is metal and expensive. In these types, the iron core slightly saturates, and this is why they feel warm to the touch. The switching types are better at conserving energy, but again making them more efficient drives up the cost.
My advice is to put all wall warts on a power strip, or if you are technically inclined replace the switching types with CEC-certified equivalants or level -V equivalents. Make sure you match current, voltage and jack polarity. Make sure any replacement wall wart has got the safety marks for your region of the planet (e.g. UL,CSA, TUV, or VDE). Cheap adapters without these marks could cause a fire or be s shock hazard, or cause radio frequency interference.