My most recent podcast addiction is to BBC Radio's Great Lives series. Great Lives is hosted by Matthew Parris. The podcast provides biographical looks at notable people. Each episode features Parris and a guest. Each guest nominates someone they deem worthy of the title 'great life' and Parris, an expert witness, and the guest then proceed to discuss that nominated person's life.
My favourite episodes so far include:
1) Lynne Truss discussing the life of author Lewis Carroll.
2) Sir Gerry Robinson looking at the life of Samuel Beckett.
3) John Harris, Parris, and Barry Miles discuss John Lennon.