George Romero is the fine wine of zombie movies.  This is one of his finest works, if not his finest.  By the way, internationally it is known as Zombi, a name that brings up some past issues with regards to other foreign films (if you want to see the worst zombie movie of all time, try to find Zombi3.  I say this is the worst, and I have seen Zombie Lake).  Anyway, an interesting trivia point from this movie is when Peter and Roger are killing all the zombies in the mall, the Muzak playing in the background is the end credit theme music (done in chicken speak) for Robot Chicken.  A nice tribute to Romero IMO.  

The original screenplay had the two last characters, Peter and Fran, kill themselves rather than escape in the helicopter.  I think I like them escaping to an uncertain future.