I agree that Napoleon Dynamite is a fun film and rather thoughtful. It has an interesting point of view, moreover, which becomes evident in the resolution. As Hunter notes, everybody in Napoleon's fictional Idaho hometown is approximately two decades behind the times, and Napoleon is held back by the community's dreary conservatism, a symptom of the people's low expectations of what they think they can hope to get out of life. Napoleon's uncle is a fine example of this acceptance of shabbiness: even though the man is willing to work, he has no direction and less imagination.
Napoleon's exasperation at just about everything around him is a symptom of his frustration at being held back by a social order that does not allow itself to benefit from creative, eccentric persons such as himself. The exaggerated languor of most of the characters, epitomized in Napoleon's brother, who does not even show the occasional bursts of energy Napoleon can sum up, is an inevitable outcome of this culture.
It is only when an Eastern, urban, ethnic element is introduced into the society, through the Internet girlfriend of Napoleon's older brother, that Napoleon and his brother can thrive. And it creates a couple of scenes that are both very funny and rather inspiring: Napoleon's dance routine and his entrance to his brother's wedding.
One could see the film as having a racial-culture angle, given that the person who introduces change to the society is African-American, but I don't think that that is at all the relevant point. The film does a wonderful job of showing how conservatism works to create social order but ultimately can suppress the creative urges that are the lifeblood of any society and any economy. For a society to function well and create a truly rich environment, there must always be a balance between conservative forces and those for reform. The title of this film aptly evokes that idea. See it.