With the caveat that there are some classics which to this day I still have not viewed. (Only so many hours in the day)
Roughly in order of preference...
The Big Heat
Kiss Me Deadly
Force of Evil
Out of the Past
Night of the Hunter
In A Lonely Place
Kiss of Death
The Woman In The Window...
It feels a bit different than my standard ideas of what comprises a noir film due to its mystery / suspense / thriller elements and its silent film influences, to name two factors. The distinctive score also tends to set the film apart. But the cinematography, the betrayal at the heart of the...
*cough* Out of the Past *cough* :)
Still thinking about my list, but I have a pretty good idea about a few of them. Robert's list is a pretty good starting point to work off of for those so inclined.