I'm one of those people who believes that the earth goes through cycles, but what we are doing to the earth isn't healthy for it. I feel it on a very personal level because my allergies are impacted by smog. I'm a big time conservationist. Don't turn on lights just because I'm in a room. Use only compact floursescent (even in my flood lights outside). Drive fairly fuel effecient cars and try to walk when I can. etc etc etc.
There is an interesting article at snopes which I can't seem to find at the moment that addresses such things as "refusing to fill the gas tank on a certain day" or "turning on your lights for a certain cause" (or in this case turning them off) and the little effect it has overall. While it may save me a few pennies to not turn on my lights for an hour, overall it does very little to effect the environment. Now if we could get everyone everyday to turn off all their lights for an hour, that may have a bigger impact on our electric use.