Conquest was the first Apes movie I saw. I still like it best of the sequels for the ideas presented and bits of verite style. The original ending is much better.
And the new Rise of the Planet of the Apes will definitely suck. I'm not even much of a Apes fan, but it looks like standard end of the world CGI action that just happens to have "Planet of the Apes" in the title. Really infuriating. Well, it can't be worse than the remake...can it?