The Road brought forth a wrenching emotional experience for which I wasn't prepared. It sort of 'grabbed me by the gut' so to say. Not a movie which is difficult to follow, but you really have to be able to dive into the atmosphere it brings. I think it approached the subject of humanity vs dehumanization pretty well, especially in the given scenario. I liked the wonderful display of symbols and references, starting with the biblical quote of Jeremiah -"Behold the valley of slaughter" at the beginning, and continuing with the symbol of fire.
The two always being near a fire and discussing made me think of the primordial fire, first brought to humans(in mythology), and with it, civilization, knowledge and light. The boy says at one point that they're 'the good guys', as they don't eat anyone and because they carry the fire (spirituality, humanity).
Another symbol was the old man with which they crossed paths, Eli. He is clearly given(now useless) prophetic valences, as he also 'warns' them of that which is about to come, then disappears from their lives. The two treating him made me think of the ancient practices of people welcoming and feeding strangers, lest they are unearthly beings. It is also the first time we notice the boy's humane nature.
To me, together the two formed one human being. Even though none of the characters are flat, the father roughly represents self-preservation while the boy is the symbol of humanity untouched in that desolating new world. I found it interesting that he is the one who reminds his father of his own humanity, when he goes back on his father's decision to go 'eye for an eye' on the man who stole from them. This in spite of the fact that the father grew up in the 'pre apocalyptic' world, when moral values were strongly present, while the boy knew not of that world, and was not influenced by it. This was to me a suggestion that man is inherently good, while innocent and untainted, even if surrounded by its most primitive and desperate urges (the presence of cannibalism for example).
The world as we know it is only represented by the recurring flashbacks and dreams.
I somewhat expected the movie to end on a positive note, at least on a personal level for the boy, which it did, as the circle never ends.
(wow, my first wall of text post)
In the case of tl;dr, I really liked this movie, I might just get the book too.