Best Hikes with Kids in Western Washington and the Cascades by Joan Burton and Ira Spring (2006)
A great guide book directed at taking your kids of all ages hiking. I love this book even when not planning hikes for the kidlets because they tend to be slightly easier and more realistically rated for people of me hiking level. Best Hikes with Dogs in Western Washington by Dan A. Nelson (2002)
This is a great dog-friendly hiking book, although it would be nice to see an updated version. Winter Hikes of Western Washington Card Deck by Craig Romano (2009)
This is an awesome card deck of recommended winter hikes. Each card includes one hike, with map and even driving directions.