Before I discuss what I thought of this film, my oldest daughter insists I talk about the film as seen in theaters. She LOVED the animation and when we watched it on Cinemax HD on our large HDTV, it apparently lost a lot according to her. A lot of the wonderful details were lost and the beauty of the film was lost--at least to some extent. Just thought I'd mention this.
As for the film, the plot is quite strange. Among the many fictional characters (though they are real in this film), the Boogeyman is intent on filling the world with awful dreams and driving out all sense of hope or joy. To counter this, Santa, the Easter Bunny, the Tooth Fairy and the Sandman all seek out a new guardian--a strange character that will help them fight Mr. Boogey. This character is the hipster-like Jack Frost. Together they do battle to save the children of the world and keep faith in them alive.
Overall, while a gorgeous film, the plot is a bit limp and is more of an excuse to show off the lovely CGI. Not a great movie but worth seeing. I especially liked Alec Baldwin as the Russian version of Santa--what an interesting accent and characterization.