I made note of this a bit ago but totally forgot to link it: Michael Blowhard offers a fascinating intro to film noir, for those who are interested but don't know where to start. I'm not the biggest noir fan, but I do enjoy a dip into that genre now and then.
And if you'd rather read some noir, grab one or both of the Library of America's noir collections, here and here.
(Speaking of the Library of America, I wonder when on Earth they plan to acknowledge Science Fiction as a genre worthy of its efforts. I love the Library of America volumes, and I wish I could still afford to be a subscriber.)