If you haven't read it yet, check out Christie's "Towards Zero."

For my money, the most "fair" novels (and TV series) were the Ellery Queen series. But they were not quite as intriguing as the locked room mysteries by John Dickson Carr, which also played fair (kind of).

There's a strange continuum: the more fair a series is, the more it becomes a puzzle. The less fair a series is, the more interesting it is as an investigation into the surprising revelations of character.