Lady In The Lake (1947)

Directed by Robert Montgomery

This Philip Marlowe hard-boiled detective (or whatever you call Marlowe) story is seriously underrated in my oh-so-humble opinion.  It relies on a somewhat gimmicky first person camera technique which some people don't care for.  I thought it was actually done very well (considering the limits of the technology it's amazing really).  Robert Montgomery is a fairly decent Marlowe, he leans heavy on the wise-cracking but that's his wheelhouse and it works for him.  It also doesn't hurt that there's a lot of great looking women in the movie.