I have to admit, I never gave The Polar Express much of a chance in years past because of it's sort of the poster boy for freaky Uncanny Valley animation, but my son and I just watched it tonight, with the speakers up loud and the lights down low and it was *mind-blowingly* good.
This may be one of those films you have to watch with a little one so you can see exactly how they're reacting and appreciate it from their point of view - but I can tell you, some of the action scenes had *me* jumping, so I can imagine it was pretty intense for him. :-) I guess they have this in an IMAX 3D version? Now that I've seen the movie, I understand why that would rock...
Totally amazing movie - definitely check it out if you haven't yet, and bring a kid along. Five years old seems just about the perfect age, trust me on that one. :-)