The second one didn't really add too much except better effects.
I would have put the original Body Snatchers on the list as opposed to the (first) remake. The second one didn't really add too much except better effects. (Mostly. Except the dog.) Even the more shocking ending isn't neccessarily a big deal, since we don't actually know how the original ended. (Some might say that's even creepier.) Plus, they really went out on a limb with the original. Considering the time a serious sci-fi flick with political undertones would have been quite revolutionary. The remake really wasn't.