Everyone knows what LED light bulbs are by now, right? The three main benefits of LED light bulbs are longer life, less energy usage, and Conspicuous Conservation. OK, that last one was a joke.
Kind of.
LED light bulbs have been around for many years, but they've been too expensive for me to justify buying. While I know they make a lot more economical sense than a Prius, I've been holding off for the prices to drop down a little further. I finally decided to buy a few last week.
I use the recessed lights in my kitchen more than any of the other lights in my house, so those are the ones that made the most sense to replace. I have 65 watt flood lights, and I probably have them on for about four hours every day - more during the winter, less during the summer. To figure out my annual cost to operate each bulb, I'll assume I pay $0.08 / kWh. The equation is 4 hours * 365 days * .065 kW * $0.08 = annual cost. This makes my annual cost to operate each bulb $7.59.

Two or three weeks ago, Home Depot had a special buy on the 65-watt equivalent LED lights, bringing the price of a 9.5 watt LED floodlight down to $24.97. My annual cost to operate one of these bulbs would be $1.11, making my annual savings $6.48 per bulb, bringing the 'payback' period to a little less than four years.
To really sweeten the deal though, these bulbs are designed to be installed without a trim kit. If you have decent trim kits on your recessed lights, this will mean nothing to you... but I have super-ugly yellow (ok - 'ivory') trim kits on the recessed lights in my kitchen, and I've actually contemplated spray-painting them white or buying new ones, but now I don't have to.
Comparisons
The photo below shows the four new LED light bulbs on the left, and two older incandescent bulbs with ugly yellow trim kits on the right. Those will be replaced very soon.

A common complaint that people have with LEDs is that the color looks blue-ish or cold, but not so with these bulbs. These looks just like the other bulbs in my kitchen - in fact, I think they look even better. I wouldn't even know these were LED bulbs if I hadn't been the one to put them in. The light output is 575 lumens, which is average for a 65-watt incandescent bulb.