The fourth book in the Inheritance Cycle by Christopher Paolini finally came out in November 2011, completing the series. Eragon, Eldest, Brisingr, and Inheritance have each come out three years apart, so after I began the third one and realized it wasn't the end, I stopped reading and decided to wait until the last one came out. I began rereading Eragon over Christmas break and finally finished Inheritance about two weeks ago.
The basic story line follows Eragon, a teenage boy in the fantasy world of Alagaesia, after he finds a dragon's egg in the woods, which subsequently hatches for him. His years-long quest to become a dragonrider brings about the deaths of many close to him, dramatically changes the lives of his cousin and fellow townspeople, and leads him on adventures and experiences he never could have imagined. It's interesting to watch Eragon grow into his role and learn the impacts of his decisions, although the reader never forgets he's sixteen throughout most of the series.
I thought the ending of the series was as good as it could be. There were a few potentials ways it could have gone, and I was worried it would be one of the ways that would cause certain characters to act out-of-character, but that didn't happen, and I think the way it ended worked better than any other way. Paolini did a nice job of leaving several doors open, and he's said he may choose to write another book about characters in Alagaesia, but not about Eragon.