I was at the hardware store earlier today buying some poly irrigation tubing -- while in line I noticed a small LED strip light that I bought to illuminate the underside of my desk (that is, the keyboard area, away from the monitor). 18", $18. Two watts. Expected lifetime: 20,000 hours.
It's fantastic that these sources are dropping in price and rising in quality so quickly. I've heard people grousing about the color balance but I'll tell you -- I haven't yet heard anyone complaining about them who didn't have a vested interest in selling something much more expensive.