I am currently writing a few radio jingles for Stroud FM Folk Programme (7-9am Tues available as a live feed).
so far I have used trad tunes (copyright demands) but any ideas welcome.
They must be instantly recognisable and simple. I put pithy lyrics to them as station identification (or sponsors' fillip).
Used so far are:

English Country Garden
Wild Rover
Over the Hills & Far Away
Amazing Grace
Drunken Sailor

Any other suggestions?