Spot metering is useful of course. Perticularly in shots that have a wide variation of contrast between objects as Pure mentioned.
But dont forget about matrix metering. Matrix is very good at metering most scenes, even the complicated ones. As a matter of fact, matrix is better at metering scenes than you are. I probably have only memorized about 30 different combinations of shutter/aperture for different scenes...whereas matrix has thousands built into it. If your camera has matrix metering, try it.
If you dont have spot metering, you can cheat the system and here's how.
Zoom into a spot in the picture that you want to meter from. Do a half-press on the shutter to meter it, and then use AE-lock to hold it. Zoom back out, re-compose and take the shot.