I've always had a problem with power. For every project, I've been wasting batteries (usually 9V ones, which aren't cheap!), or fuddling with a rat's nest of wall warts. I recently saw this
instructable on how to make a cheap power supply out of a computer ATX power supply. So I also headed over to this
site for more detailed instructions on how to do it. I took an old Dell E310 desktop, and ripped out the power supply. It gives me 12, 5, and 3.3V DC for use with future project testing, and has a green indicator LED which will turn off in the case of an overcurrent, overheating, or any other related error. The red LED on the switch is simply to indicate it is getting 120V AC power.