I would have to agree with Skar and Stacer. Originality is really not that important.
Usually, when someone says something is original, it means that they have not persoanally seen something like it. But when you start nit-picking, you can usually find plenty of unoriginal elements.
And still, alot of it is based on what your personal background and experiences had givin you. On of the great things about the children's market is that they see almost everything as original. Just look how they are bringing back toys from fifteen years ago. To the kids getting these toys, the new versions are the original ones and the old versions are the copies.
Every once and while, something truly original shows up, but it's not worth holding your breath for it. One theory of Aesthetics says that nothing is original, everything stemming from some premortal existance.
For everyday criticism, orignality kind of needs to take a back seat to things like craftsmanship, social relevence, and market demands. Bad critics get so focused on finding originality, that they tyically end up jaded and dissappointed almost every time.