He makes my absolute favourite kind of film: comedic drama.
I think it's important to make the distinction, and not to assume that any film that is funny is necessarily a comedy.
For instance, lukeii tried to claim that Casablanca is a comedy, which I think is absolutely not the case (although it is definitely funny).
Robert McKee has an interesting definition of comedy, which I don't necessarily agree with 100%, that states that if you take out all the dialogue and all the non-essential action, and you just retell the story, if that alone makes you laugh then it's a comedy, if not then it's a drama (funny or not).
By that definition, Casablanca is absolutely not a comedy, since the story itself is all about heartbreak and Nazis.
However, that definition of comedy is in turn both too narrow and too specific.
Too narrow because it means that there would be very few movies that would actually come out classified as comedies (think of the story of, say, Wayne's World, which would come out of that analysis as a romance and a David and Goliath type drama, and it is quite obviously a comedy, by anyone's reckoning).
Too specific because of films like those of Wes Anderson (I got back to the topic eventually).
Take out the dialogue, and lay bare the story of a Wes Anderson film (most of you are probably most familiar with The Royal Tenenbaums), and there are plenty of elements that are in themselves funny, but then of course there is plenty of "drama" and sadness.
Anyway, my point is, I feel that his films are dramas, but at the same time they make me laugh so hard I think I'm going to wet myself.
All in all, I thought The Life Aquatic was a fantastic film, although not quite as good as The Royal Tenenbaums (but to me that's like saying Kerry Packer is not quite as rich as Bill Gates).
And I absolutely have to get the Life Aquatic soundtrack, but I won't say why because it would be a spoiler.
Another observation that I made was about Willem Dafoe.
He seems to have an uncanny knack of stealing the show, when he is not the main actor.
See also: Spider-man, The Boondock Saints and perhaps even Finding Nemo.
Look out for him in XXX2, or don't, since it has Ice Cube instead of Vin Diesel.
Alfred Molina is also a true master of this particular trick (Spider-man villains = show stealers!).
See: Spider-man 2, Magnolia and, in particular, Chocolat.