I just finished Red Country - latest book in the First Law world. It's at least as good as the others, and revisits a few characters we've seen before to show how the intervening years have treated them.
The main story is great too - Abercrombie's ability to make characters (even horrible ones) human is here in full force. The story takes them to a piece of country that's an obvious parallel to the US West. The story isn't exactly a fantasy western, but that's a pretty good quick description.
Recommended! But read the other books first (knowing the history of the returning characters adds a large dimension to the story).