You've got to include some George Romero.... Any and all of the Romero and Romero-inspired zombie movies are good, i.e.,
Night of the Living Dead (1969 & 1990)
Dawn of the Dead (1978 & 2004)
Day of the Dead
The
Return of the Living Dead movies are good too (well, the first two anyway), if you like a little more humor in your zombie apocalypse tales.
Oh, yeah, Lucio Fulci's
Zombie is good, and so is Michele Soavi’s
Dellamorte Dellamore (aka
Cemetery Man, 1994)!