So far, the two main nominees are:
The original One Million Years B.C. starring those lovable lizards with paper fins
and
The Last Dinosaur, a rubber-suit special.
I personally have a soft spot for the original _One Million Years B.C._ -- IMHO the girl in that one was cuter than Raquel Welch.
I'm not partial to the _Land Before Time_ series -- Another story of icky-cute herbivores and evil, wart-infested theropods. But I always tend to let animations off easy, so my vote goes for _The Last Dinosaur_. (Oh wait -- Does the live-action _Flintstones_ count?)
-- Dave