Dante Stella, The Machine Planet:
Spot meters help you sort out the various tones in a scene so that you can spend 1000x the effort to get a picture that is 10% better than an averaging reflective meter used correctly. Spot meters, like communism, seem like a great idea until you try to use them on an everyday basis.
I once said that spot meters are for posers. Dante seems to agree :). Other than some fine snark, the rest of the article contains a lot of good information about light meters.