My most favorites tend to be British and a bit old-fashioned. Ngaio Marsh, P. D. James, Ruth Rendell. Outliers include Iain Pears, Kate Ross (alas, only four books), Faye Kellerman, Jeffery Deaver (who is kind of not like the others). Both Martha Grimes and Elizabeth George I fell off of. I'm sure I'm forgetting some, but that's probably a good overview of stuff I like. :)