A great book series is like a coin; there are 2 distinct emotional sides to finishing it.
On one hand, you have that extremely satisfied feeling at the end - a mental burp as it were. On the other hand, there's a mild sense of loss, knowing that the pages, plots & permutations (awesome alliteration!!) are no longer new. The feeling is similar to knowing what your birthday gift is before you unwrap it.
And yet, a gift is always welcome. Having finished the Millennium trilogy yesterday, there's quite a churning in the emotional barrel. The books are very well written & for that, I'm a little sad that there are no more in the series. But reading these books has fanned the dying embers of my book-reading patterns. I know with certainty that I'll be reading a lot more.
In my world, there's no loss in that development.
Song for the moment: The night is still young - Billy Joel