Land of the Dead - visionary
No numerical rating. It has many bad things done in ways that are bad in modern horror movies, such as the uber-dark lighting/contrast work. It hits home more when the lighting appears natural, guys. But, a numerical rating doesn't cut it, just like it doesn't for the original. Also, it's kind of out of place in the series, being that it was produced like a mainstream movie, where the previous ones were made more like cult films.
Still, great plot, great acting (you could tell the actors were really having fun, especially Asia Argento and Dennis Hopper), and most wonderful use of the zombies. It picked up in those terms perfectly after the other films (what was learned of the zombies in Dawn and then Day). The zombies cooperating, and the humans in charge not "getting" what the world is like (George Romero loves the Bush administration?), etc., were just mind-blowing, shown in ways that only film can.
At this point, for me: Night > Land > Day > Dawn > Dawn ('04)