I seem to recall Kingstonian mentioning Elmore Leonard.  His early novels are cracking.  Same with Ed McBain (to whom I once wrote for an autograph, so keen was I on Carella and those other Homicide types). 
As for the great Simenon, if you haven't yet, do so...  For sheer atmosphere, the above mentioned...  Goes nicely with those French movies Yuca, Gibson and I like.  The man himself was a bit of a monster (if we are to take the word of his biographers) to say the least of it, but, then, Picasso was no angel, was he? 
There are plenty of others worth picking up: Kemelman's 'Rabbi' novels, more or less anything by Horace McCoy, early George V. Higgins...