If you were interested by the list of the UK's 100 top sellers of 2005, then you may also care to look at the Book Standard's list of the top 200 sellers in the US.
At number 194, for instance, we have William Golding's Lord of the Flies. This was not a very exciting or satisfactory book even when it first came out, in 1954 (and I speak as one who taught just such classes of small boys), but it is widely held to be Significant, and is, I gather, much taught in US colleges. Which just goes to show how profitable it can be to get on to the essential reading lists of the Eng. Lit. guys. Unfortunately Golding died in 1993 so he isn't around to benefit personally.