Why is the APU located in the tail for almost all commercial aircraft? I know there are planes whose APU (Auxiliary Power Unit) is located elsewhere, but for the most common commercial jet aircraft (A320, B737, B747, A330,...), the APU is located in the tail.

Is there a good reason for that (place, weight, airflow,...)?
Dead space... Not much room in the tail to put other stuff, and it fits. Plus it has a nice empty space just outside for the exhaust pipe to exit without the hot gasses hitting anything.

Put the APU in the nose and you need a long pipe somewhere to get rid of the exhaust. More weight, more space, etc.
Put it in the wing and you're looking at uneven weight distribution (you want it at or near the centerline).
Leaves the tail area as a logical place, and there just happens to be space there as well in most aircraft.