Only 10? Scary to make this decision, but here goes..... in chronological order also and with the one per director rule.

Sunrise (1927) - F.W. Murnau 
Vredens dag (1943) - Carl Theodor Dreyer 
Journal d'un cur de campagne (1951) - Robert Bresson 
Tokyo monogatari (1953) - Yasujiro Ozu 
Vivre sa vie (1962) - Jean-Luc Godard 
Professione: reporter (1975) - Michelangelo Antonioni 
Stalker (1979) - Andrei Tarkovsky 
Sans soleil (1983) - Chris Marker 
Paris, Texas (1984) - Wim Wenders 
La Belle noiseuse (1991) - Jacques Rivette 

It's really hard to have much confidence in this list because it's so small and because i was unsure of leaving about 15 more out. Cassavetes was the hardest director to leave out.