Another book recently published which features journal entries, along with letters and emails, is Operation Homecoming: Iraq, Afghanistan, and the Home Front, in the Words of U.S. Troops and Their Families.
I discovered this book through a news story here, which has a great write up on the book. I was most impressed to find the editor was overwhelmed with submissions for this book, even though he expected few entries. The stories offer a glimpse into the personal tales of these brave men and women.