Cormac McCarthy is a bonafide genius. Blood Meridian may be one of the most effective horror novels I've ever read, and the Border Trilogy has some of the most hands-down beautiful prose I've ever read. But The Road? Definitely in a class of its own. I agree with Alison that it compares to Russell Hoban, or even George Stewart's Earth Abides (which are both excellent novels as well), but is certainly not easily pegged into some comfy category.