If you're already reading Elmore Leonard, you're reading the best. He's definitely crime fiction, and focuses a lot of times from the criminal's POV, or someone on the fringe of criminality, maybe someone flirting with a scam that gets caught up with something bad. I've read about six of his novels and find his writing to be the most pithy with the best dialogue.
The other suggestions in this thread are great. I agree with Carl HIassen and Michael Connely, both great crime writers; Hiassen leans more towards Leonard, while Connely (I've only read Lincoln Lawyer so far) seems to come more from the good guy's POV.
James Ellroy is also fantastic. His Black Dahlia and LA Confidential rock. Just ordered a couple more of his novels. He comes more from the PI/cop POV, but with very engaging characters, well-rounded and flawed--boy, are they flawed! His amount of detail regarding the job of a policeman and the research/detail behind his period settings are so good and believable they intimidate me completely from writing a police procedural, especially one set in a past decade.
Don't forget the classics... Raymond Chandler and Dashell Hammett started it all for today's guys. They're both a little heavy-handed with their description (a sign of their times), but their characters and plotting are top-grade.