I'm going to throw in another vote for Planet of the Apes (though it won't let me actually vote in the poll because apparently I haven't posted enough in the forums). But yeah, your order is off. The original five movies in release (and far and above best viewing) order are:
Planet of the Apes
Beneath the Planet of the Apes
Escape from the Planet of the Apes
Conquest of the Planet of the Apes
Battle for the Planet of the Apes
Technically speaking, chronologically, the order would be Escape, Conquest, Battle, Planet, Beneath, but please, please do not watch them in that order. I am also a chronology nut, but once you've watched them all in release order, I think you'll totally agree that it's the best way to watch them.
Chronologically, after these five movies, next would be the Planet of the Apes live-action TV series. I've watched half of it, and it's slow, but I've enjoyed it so far. As for Return to the Planet of the Apes, the animated series, I haven't yet watched it so I don't know exactly where it fits, but it is in the same universe as the original movies. It came out last though, so I'd probably just watch that one last if you're still interested.
If you'd like to watch every movie (which I think is a great idea), the next one to watch would be Burton's Planet of the Apes from 2001. It is a remake of the original Planet of the Apes, but it takes place in a separate universe and is completely incompatible with the others. I'm not a fan of this one, but it is interesting to see.
Finally, watch Rise of the Planet of the Apes and Dawn of the Planet of the Apes (whose titles really ought to be swapped, if you ask me). This is a fresh reboot of the series, though, as another stated, they most closely align with the plots of Conquest and Battle from the original series. They are both excellent, though very different than and entirely incompatible with the original series.
Have fun! Though some are certainly better than others (please don't give up after Beneath - it may be terrible, but Escape is so good!), I think you'll enjoy the ride. It's a fantastic series.