Billy Wilder (classic, I do not know him well, I wish I knew more)
Sergio Leone (crowd pleaser, knows how entertain people, I love him)
Ingmar Bergman (first true, serious director in the list, great researcher of human soul, underrated on this list)
James Cameron (hands down the most skillful technically brilliant modern director, who has A scores on every single aspect of film making, very successful commercially, proved to be able to excel in different genre, I love him)
Ridley Scott (same here, although I hate Blade Runner)
David Fincher (great director, love his cinematography, poor choice of score composers lately, a bit too much of himself)
Sidney Lumet (I do not like him)
Peter Jackson (what the heck this bloody mediocrity is doing here? he is a crowd pleaser, definitely not my crowd)
William Wyler (irrelevant now)
Francis Ford Coppola (uneven, brilliant, love him)
Federico Fellini (way, way underrated, brilliant director, both spectacularly entertaining and serious at the same time, love him)
Clint Eastwood (probably the top most actor-director in this category, American Sniper is a faux pas)
Frank Capra (classic, I have seen only one movie of him, which I love dearly: IAWL)