I am a mother of a three year old and someone who enjoys a family themed movies. Here are some titles of movies that I don't mind watching more than once. They are arranged in what I believe to age appropriate categories

To start I would recommend the Land Before Time Series. Has decent characters and there is usually a good moral to the story. Each character tends to mirror different toddler personalities. My son states he is best friends with Littlefoot!

Any of the Disney Classics.. You are never too young (or too old for that matter) to watch a good Disney Classic.

Ms Spider is also a good series to watch. The characters also mirror toddlers personalities and there is good moral to storyline.

Charlotte's Web is another great movie... ( not the animated version). My son used to watch it over and over again..If you can get past the talking spider it is a fun film :)

All of the Shrek movies are a must. The are just as entertaining for children as well as adults. My 3 year old likes to watch it but I believe a lot of the humor is lost on the really young children.

Here is a movie I liked, which will no doubt date me,.. The Neverending Story..Flying on your own dragon, saving the princess from fantastical people.. what's not to like?

For the magically thinkers, Harry Pottermovies are also a great gift. This movie is recommended for the older viewers. I think some parts of the movie are very intense for little ones. (I am thinking about the scene where Harry and his pals are surrounded by giant spiders. ewwwww)!

Lord of the Rings Trilogy is also a good one for the older viewers.

Anything recent by Pixar Studios. Walle, Bee Movie, Kung Fu Panda are sure winners, and will be collectors versions if they are not already.

I actually saw at walmart a  collection of Bugs Bunny cartoons.  Too expensive for me a the time.. but it would be a wonderful addition to any cartoon collection.