However, if I would have to pick two of my favorite movies from each of the aforementioned directors I'd pick these:
George A. Romero:
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#1) Day Of The Dead (1985): I absolutely love this movie and think it's far superior to Dawn Of The Dead in may ways. The story not only has a very desperate, claustrophobic feel to it, but it's pretty much everyone's nightmare come true. Imagine being trapped underground with a bunch of evil fucks with machine guns and the alternative is combating the undead and probably being eaten alive. I also feel that this is Tom Savini's best movie special effects wise and has some of the best gore from the 1980's.