Midsomer Murders and Murdoch Mysteries are good British detective shows, and I've mentioned my love of Luther and Prime Suspect in the other thread. I also liked the updated Sherlock Holmes series with Benedict Cumberbatch.
The show I'd like to see brought to the big screen, or at least television, is Phil Rickman's Merrily Watkins novels. The title character is a CoE priest who specializes in "Deliverance" - that is, exorcism - and finds herself up to her neck in all kinds of trouble as a result, from villains both supernatural and corporeal. I'm just not sure how well Rickman's atmospherics - for the most part, his novels are set in the mystic, haunted and moody Welsh/English border country - and characterization would translate to TV. For that matter, Rickman has several standalone, and standout, horror novels in a similar setting - Curfew and December come to mind - that have been begging for a movie to be made of them for years.