I don't pretend to be any sort of scholar where film noir is concerned, but like most movies geeks of a certain age, I was bitten by the bug and went a little crazy. All of a sudden my Netflix queue was swollen with films by Jules Dassin, Robert Siodmak, and Anthony Mann. I must have gone through at least 50 titles, but my very favorite remains the first noir I ever saw: Otto Preminger's practically perfect Laura. As most old-school movie freaks can tell you, film noir generally deals with several key components: Crime, paranoia, sharp shadows, hard-boiled dialog, elaborate conspiracies, femme fatales, sudden violence, and a foreboding sense that fate is a cruel mistress indeed. (Like I said, I'm no scholar, but you can get a great noir lesson right here.)
But nowadays we don't seem to have much use for film noir, unless (of course) it's used as a stylistic choice in movies like Sin City and Watchmen. (Hey, I guess Frank Miller and Alan Moore dig film noir, so maybe you should too!) And then there are indie films like The Perfect Sleep, which aim to come across as both a traditional film noir and an affectionate homage / satire of the genre at the same time. If the flick is just a bit too clever for its own good on one or two occasions, well, I suppose that's preferable to most movies, because they're generally way too stupid for their own good.