My letter box is a pillar box - I live in the Old Post Office, so I've got a bit of a theme...
I've painted the pillar box F+B French Grey (to match my garage doors etc.) and had a sign made to replace the collection times plat,, giving directions to the nearest posting pox and the nearest post office.
I live right on the "main" road, so many people pass the box - only had one lady post letters in it so far.
There is another pillar box - now letter box in the village. That one is black and it's not visible from the highway.
ooh please tell us more... have you got a nice old post office bicycle with flowers in the basket out the front? And have you got stamp collections on the walls? And post office scales in the kitchen? And a black and white cat called Jessie? And do you communicate with people in the house by letter?
Sorry, I love themes, I tend to get a bit carried away with them though!