I know there are two kinds of DC-DC regulator: linear & switching. However, I'm not clear about how to determine which one is suitable for a particular application ? Hope you might give me some examples.

 

You have to describe about your particular application, V, I, W, circuit, any details.

 

Linear regulators are simpler and generally cheaper, and switching regulators are more efficient. So it really depends upon the application requirements as Scott mentioned.