Choosing the right microphone could make the difference from getting just good audio to great sound. Depending on what you are trying to record, choosing the right microphone could result in better dynamics, sound quality, less noise and an overall better recording.
Microphones come in all sorts of different styles and pick up patterns. For example, a cardiod mic will have unidirectional pattern that is shaped like a heart. This is a great utility mic and is good for vocal recording.