Shaggy from Scooby-Doo is Brian Speer in The Descendants: Book VS Movie

In The Descendants we know early on that Matt King suspects his wife of having an affair, a suspicion confirmed by daughter Alexandra. In fact, it's this affair that causes Joanie (Elizabeth in the film version; a name change I'm still trying to understand) to send Alex back to boarding school on the big island. The mother and daughter are furious with each other, and Matt, with his characteristic cluelessness has no idea why Alex is so angry with her mother or why her mother ships her back to the Hawaii Pacific Institute. We learn later that the object of Joanie's affection is Brian Speer, an island realtor. "Realtor" is pretty much code for sleaze - I'm a realtor myself and am all too aware that most people regard real estate agents with the same amount of respect they hold for used car salesmen - not a lot! So the reader understands instantly this is shorthand for what will probably not be the nicest guy. Then again, if he and Joanie truly love one another, perhaps he's redeemable? The casting of this smallish part must have been dicey—in the book at least, there's much more thinking about and looking for Brian Speer, than there is actual Brian Speer. The comatose Joanie/Elizabeth was a model and is still gorgeous so is he the typical glossy slickster with bright bleach white teeth, a veritable smooth operator? Apparently director Alexander Payne checked out that type before he landed on Matt Lillard. Who? Matt Lillard, the young, likeable goofball we know and love from the Scooby Doo movies and Without a Paddle. Except Matt is not so young anymore as you can see from the picture above at the New York Film Festival's American premiere of the film. But he is still likeable! His interview with MovieFone  is a must-read; I hope you'll check it out! Let me know what you think; is Matt Lillard the perfect choice for Brian Speer? If not who do you think would have been a better choice?