For some reason, it didn't come to mind as a series, but I'm two-thirds of the way through Cormac McCarthy's Border Trilogy. Perhaps because I've got it all in one volume. I'm having a bit of a rest between each book of the three, because although I love the language, the style wears me out!
The Millennium Trilogy - Decent enough books, and I was delighted to see Sven-Bertil Taube back on the screen after all those years. Put Daniel Craig into the original film and you'd have a much better mix.
Clive Cussler's Dirk Pitt novels - required holiday reading in the early 80s but can't be bothered in the last fifteen or so years. Went downhill when the main character kept meeting the author in the stories...
Donald E Westlake's Dortmunder books. Westlake was always good value for an easy read with some great twists, and while the Dortmunders probably weren't my favourites of his, they definitely count and I'd read them again tomorrow.