To be honest, the trailer is rather ill-judged. By opting to show nothing but a whole load of funny slapstick bits it makes the film look like just another by-the-numbers animated comedy, and the use of Kung Fu Fighting AND that tune from Kill Bill as background music was a real mistake - they're possibly the two most uninspired pieces of music that anyone could possibly have chosen, and this doesn't give a positive impression about the amount of creativity you can expect to see in the movie as a whole (particularly unfortunate since, as mentioned previously in this thread, neither tune actually appears in the film). Erk.
Far, far better is the newly-revamped Kung Fu Panda website. It's still massively incomplete, but it seems to offer a far better flavour of what the film is actually going to be like. From what I've been reading from assorted folks who've been to recent screenings, the movie is frequently dramatic, tense and exciting and doesn't attempt to pepper the audience with gags at every turn, with authentically-choreographed fight scenes and moments of darkness that give the proceedings considerably more depth than the likes of, say, Shark Tale - and the new site certainly reflects this, particularly in the character bios (with brief rundowns on everyone's fighting technique of choice, which are actually quite informative) and the tour of the Jade Palace.
The latter section is especially impressive because of all the stories atteched to the various weapons and other artefacts that you can look at. There are one or two funny bits, sure, but for the most part the stories have an authentically mythic air to them which is tremendously refreshing and, on one or two occasions, actually quite affecting (the tale of the steadfast warriors killed by a horde of demons while defending a village being a particularly good example). It creates an impression of a world where actions have serious consequences (as opposed to a Tom and Jerry-like scenario where you can get hit in the head with an axe and be up and running about a few seconds later) and villains pose a real threat, and this serves to create a much more inspiring idea of what you can expect from a film which is, at its core, about heroes answering the call to battle some evil villains. I'm looking forward to seeing the additional content that's set to be added to the site...
All in all, Kung Fu Panda is the first animated film that I've been genuinely excited about seeing for some considerable time. Let's hope that the next trailer (and there's bound to be at least one more before June rolls around) focuses on the story and the serious elements a bit more, eh? Some shots of the baddies wouldn't go amiss, either. Even the teaser with Jack Black in his pyjamas showed a little footage of Tai Lung.