OK, the zombies look like old men with bad makeup after a night out drinking.  Hard to believe that this movie had the effect on people that it did when you really look at it. 
But most of us agree that this is a great movie.  Not just because this is the one that started it all, but also because it is very creative considering the time in which it was made.  Consider that Romero had little in the way of previous horror movies to borrow from.  Not that he did not borrow a little, but there had been nothing quite like this one before it.  Not only did he create a new way of making horror films, but he created an entire genre that is still strong 40 years later.  I wish that I had done something so cool in my lifetime.
I actually read a thread on that blasted Romero.  The writer added that all of his movies were bad and that he was unimpressed with the 5 DVD boxed set.  The writer was also evaluating this movie from 1968 against current movies such as 28 Days Later.  28 Days is a phenomenal movie, but it also has 40 years of theatrical progress on its' side.  Not to mention that the plot borrows fairly liberally from NOTLD.  The pace of 28 Days would have been unheard of even 20 years ago.
The film begins in a cemetary and it does not take long before something real bad happens.  We see a man in a suit with a lumbering gait that just does not look right.  He attacks the man and the woman flees.  One of the strengths of this movie is that it develops very quickly and there is no delay in the action.
Romero's next major contribution to the future of horror is the isolation of the characters.  This is a theme that is used as frequently as gore in horror films yet today.  They find themselves holed up in a farm house, able to rely solely on themselves.   The film then details an epic battle between the people in the farm house and the zombies, which seem to be larger in number by the minute.
Most everyone knows how this one ends already, so I won't dwell on the details.  I cannot praise this film enough.  It was way ahead of its' time and influences films today, 40 years later.