Some of the more obscure 'Golden Age' detectives are entertaining. Max Carrados, (Ernest Bramagh) for example, who is blind but seemingly omniscient, and John Dickson Carr's characters Dr Fell and Sir Henry Merrivale. I also like Nigel Strangeways - created by Cecil Day-Lewis (writing as Nicholas Blake) and in his first outing based on the young W H Auden. My favourite of the classic ones, though, is Lord Peter Wimsey.
Of more recent ones, I am a recent Pendergast convert too.