Last year I decided to keep track of the books that I read using a Google documents spreadsheet. Looking at this list, it looks like a plurality of the books were actually mysteries, and all of these were actually from small specialty publisher Crippen and Landru. It looks like I read of total of 37 of their books last year. It was definitely time well spent.
Crippen and Landru specializes in printing or reprinting classic detective stories. They seem to emphasize the type of story in which the reader is shown all of the relevant clues before the story's protagonist solves the puzzle. I prefer those type of detective stories over the stuff that's popular these days that I'd say is better classified as crime fiction instead of detective fiction.
In any event, Crippen and Landru publish two lines of limited edition books: Lost Classics and their regular line. The Lost Classics line reprints material that's fairly good, but not widely known. Examples of this are detective stories by Rafael Sabatini, who's better known for writing Captain Blood, or detective stories by western pulp writer Max Brand.
The regular line collects short stories from contemporary writers and its books include all sorts of interesting extra stuff. Some of the books include a page from the original typescripts for one of the stories in the book. Others include a short pamphlet that contains a story written by the author just for inclusion with the Crippen and Landru limited edition. All of them are signed by the author, and they'll probably be fairly valuable one day. Every one of these has been extremely good.
I still have quite a few Crippen and Landru books that are still unread. But since they're easily outnumbered by the stacks of unread books that don't contain any mysteries at all, there's no guarantee that my list of books read in 2010 will have the same bias.