A Storm of Swords - George R.R. Martin
This book was the reason there is all sorts of hooplah about this series. This is the fantastic one. I actually had my jaw hanging open in complete shock near the end of this book. This book is why I bought the series and am waiting with baited breath for my hold to come up at the library.
I should also mention that I am enjoying the references to Egg and Ser Duncan the Tall built into this book. I don't know how many people caught that but if not, go and read Mr. Martin's stories in the Legends books.