I hate zombies. They are the least inventive of all the classic monsters, and the most limited and boring. The zombie takes its name from the Haitian voodoo practice of allegedly reviving dead corpses, but in truth the zombie as currently practiced is little more than a degraded vampire, with little relationship to Haitian lore, which involves a voodoo priest, magic spells, and walking corpses bound in service to sorcerers.
By contrast, the modern zombie is essentially a vampire without a brain. Both are risen corpses. Both feed on human bodies to sustain their unnatural existence. Both use their teeth as their major weapon. The differences between the two are traceable to the origins of the vampire story. The original vampires of European folklore were essentially what we would call zombies: rotting corpses rising from their graves, feeding on human bodies (not always blood--sometimes flesh, sometimes "breath"), and essentially mindless except for their insatiable, animal hunger. Only in the nineteenth century, with John Polidori's The Vampyre, the penny-dreadful Varney the Vampire, J. Sheridan LeFanu's Carmilla, and of course Bram Stoker's Dracula, was the unattractive, repulsive, rotten corpse-fiend replaced with aristocratic, cultured blood suckers.
With vampires becoming objects of lust rather than terror in the twentieth century, suddenly phalanxes of zombies started marching across popular culture to return the risen corpse to its (un)natural state. However, the modern zombie lacks the Gothic gloom of the folkloric vampire, the sense of holy dread that ancient creature caused in the peasants who cowered in fear before it. The modern zombie is mostly canon-fodder, meat sacks to blow up to fill some visceral blood lust that stands in opposition to the feelings of terror and dread good horror is supposed to produce.