Spot metering is useful anytime there is a strong contrast between subject and background, or when the dynamic range of the scene is very wide. You either find the thing in the scene that you want to have a neutral tone, or you meter on something that you know should be a certain amount above or below neutral and adjust accordingly.
Examples are: snowfields, nighttime shots, strongly backlit shots, beach scenes, water scenes, ... All of those can easily benefit from spot metering.
Also, if you are using the "Zone" system, a spot meter is one of the best tools for making your evaluation. For a simplified approach on the Zone system, look here:
http://www.luminous-landscape.com/tu...e_system.shtml
Duffy