Top to bottom film noir is the richest of any film genre. Below are my Top 25 found in the Naro's Film Noir section in the annex (except for those found on an individual director's shelf as noted).
1. DOUBLE INDEMNITY (on Billy Wilder shelf)
2. THE SET-UP
3. TOUCH OF EVIL (Orson Welles)
4. OUT OF THE PAST
5. THE BIG CARNIVAL (aka ACE IN THE HOLE) (Billy Wilder)
6. THE BIG HEAT
7. THE WRONG MAN (Alfred Hitchcock)
8. PICKUP ON SOUTH STREET (Samuel Fuller)
9. CRISS CROSS
10. SWEET SMELL OF SUCCESS
11. NIGHTMARE ALLEY
12. SUNSET BLVD (Billy Wilder)
13. DETOUR
14. GUN CRAZY
15. IN A LONELY PLACE (Nicholas Ray)
16. LAURA (Otto Preminger)
17. NOTORIOUS (Alfred Hitchcock)
18. ON DANGEROUS GROUND (Nicholas Ray)
19. CRIME WAVE
20. THE BIG COMBO
21. THE KILLERS (on Don Siegel's shelf, tho this version is not directed by him)
22. NIGHT AND THE CITY
23. THE KILLING (Stanley Kubrick)
24. GILDA
25. SCARLET STREET