There's an interesting discussion going on at http://www.crimefictionblog.com, started by David Montgomery. It talks about private eye clichés and of course I've joined the discussion too as well as guys like Sean Chercover.
I submitted my own Noah Milano to the list.
*The psycho sidekick who does the dirty work so that the hero can keep his hands clean. While Noah has two sidekicks (his mentor Kane and his buddy Tony Hawaii) he doesn't keep his hands clean, often breaking the law to get the job or justice done.
*The detective who's a gourmet cook.
Noah's specialty is a phone call to Domino's.
*The detective who drives a flashy car. (Would you really try to tail someone in a Ferrari or Shelby Cobra?)
He drives a flashy Dodge recently but used to drive a regular Mazda.
* The detective as social worker -- not only does he solve your case, he heals your soul.
Noah helps out several people (notably some teenagers in White Knight Syndrome and Good Girls Bleed Too, see the sidebar My Writings for details).
* The detective who's a gimmick instead of a character: he loves Bugs Bunny, he's got OCD, he's a leper, he's a left-handed transsexual, he thinks he's from Mars, etc.
Noah is the son of a gangster. Gimmick? Personally I consider it an interesting element to build stories around. Also, he loves comics and rock music. Those aren't gimmicks, they make him a person.
In the end this discussion might benefit the genre because a lot of people seem to be joining in and as they say better bad publicity than no publicitiy. Tackling these cliches might in the end show people the PI genre has certain common elements but is also an enjoyable one with many good writers working in it.
Lori Armstrong, author of the Julie Collins series gives her own oponions at http://www.firstoffenders.typepad.com/. I totally agree!