Here's some of the things I've done to save energy on this side of the pond that had relatively little in investment, if any, but had pretty good returns:
Converted most of my incandescant light fixtures to using CFL's. I love those new "daylight" ones! I don't like lots of light anyways, so i bought some of the 9 watt models and replaced all my 60 watt bulbs
Turn lights and appliances off in rooms I'm not occupying..
Take a shower at night, then turn the water-heater off before I go to bed. Turn it on again the next day when I get home from work, and do all my water-based chores after about an hour or so...this way, the water heater is sitting at least 18 hours without consuming any electricity.
Plugged appliances that take "standby" power all into outlet strips, then turn off the strip whenever they're not being used...IE appliances with clocks, wall-wort AC adapters, etc.
I planted some maple trees on the south side of my house. During the summer, their leaves block sunlight from getting to the house and heating it up, and thus keep it cooler. During the winter, they loose their leaves, and allow the sunlight in the windows, thus warming the house.
Planted some low shrubs around the AC compressor to keep it out of direct sunlight.
swapped my low-voltage landscaping lights for solar LED ones
Installed ceiling fans in the most commonly used rooms. During the winter, they run on low in the updraft direction to push warm air away from the ceiling. During the summer, they run on medium downdraft, and then I don't need to set the AC as cool.
...so far, these ideas have made significant savings! My electric bill this summer, even during the hottest part didn't top $84. During this past fall when I had the HVAC systems off because the weather was comfortable, it got as cheap as $37!