Although his character's name appears last in the title You, Me, and Dupree, Owen Wilson's name is first in the credits and he's the most prominent character in the billboards.  This is very telling, as it shows that the movie is really about his character, and not about the newlyweds that he intrudes on.  It is also telling that Matt Dillon is the new husband.  Dillon (Herbie:  Fully Loaded, Crash) is known more for playing bad guys rather than good guys.  Dillon is Carl Peterson, now happily married to Molly (Kate Hudson, The Skeleton Key, Raising Helen).  Dupree (Wilson, Cars, Wedding Crashers), is Carl's best friend, a dopey guy who parties incessantly.

Dupree is Owen at his best.  He plays similar characters in many movies, and it feels like he's coasting along here.  Dupree is very likeable but highly irresponsible.  He's the life of every party, but once Carl settles down, Dupree becomes more of a nuisance than anything else.  Through some vague circumstances, Dupree loses his apartment, and Carl invites him to stay at the Peterson house, albeit for a few days.  A few days quickly becomes longer, and chaos seems to touch everything that Dupree does.  Meanwhile, Molly's father (Michael Douglas, The Sentinel, The Beautiful Country), who also happens to be Carl's boss, disapproves of the wedding and begins to overwork Carl on purpose.

The whole thing becomes a slow powder keg for Carl.  Interestingly, screenwriter Mike LeSieur and directors Anthony and Joe Russo (Welcome to Collinwood) slowly change the shift of audience sympathies.  At the beginning of You, Me, and Dupree, the viewer sides with Carl.  Dupree is a slacker and is mooching off the goodwill of his friends.  He's bothering the new husband and wife with antics that the audience already knows because they're in every trailer.  But slowly, Carl becomes more of a jerk, and as Molly and the audience learn more about Dupree, they begin to side with him.

There are a few problems with You, Me, and Dupree.  The main one is that the trailer gives all the jokes away.  And the jokes are not that funny.  Wilson, Dillon, and Hudson, all good actors, are working with very thin material.  This is a retread of a role that Wilson has done before, and a retread of countless other movies.  The Russos do not add anything original to the film, just relying on formula and Wilson to try to elicit laughs that never come.  You, Me, and Dupree never gets to the point where it's bad, just very uneven.