I know wireheads who can tell the value of most resistors just by looking at their color bands. I am NOT that kind of geek. I’m the lazy kind. I’m the kind that thinks it’s not too much to ask for the values of components to be printed on them. I mean, Jeez, they can laser-etch logos and UPCs onto individual pieces of fruit now! Anyway, I use my trusty ol’ RadioCrap Resistor/Cap Color Code wheel to figure out what components I got stuck with in my Taiwanese parts grab bag.
This nifty OS X Widget works the same way. You enter in a resistor color sequence and it gives you the value, or you enter in the value you desire and it shows you the color code you need to look for on the resistor itself.
Tip: When you get a new pack of resistors, sit down with your color code wheel or widget, look up the values, and mark them down on the reel tape that holds the resistor sets together. Then, use wire snips to cut resistors off as you use them, leaving the reel tape in place. This way, the resistors are marked until you snip the last one from the tape.