My own next-favorite urban fantasy author after Simon Green and Jim Butcher is probably Ilona Andrews and the Kate Daniels series-- starts with Magic Bites. Seanan McGuire's October Daye books (starts with Rosemary and Rue) and Patricia Briggs's Mercy Thompson books (starts with Moon Called) are close behind. Those are more straight-up urban fantasy than noir, though. Hmm, let's see {checks reading list}...

For fantasy noir, Mike Carey's Felix Castor books are very similar in feel to Simon Green's Nightside. The Devil You Know is the first one of those. Likewise Kate Griffin's A Madness of Angels and its sequels. For sci-fi noir, I just finished Adam Christopher's Empire State, which is very weird but pretty good for a debut novel.

Sadly, none of this is cheap/free; I've rarely found anything in that category that's worth recommending to others.