You know how the little star trek icon by the posters name in the "last post" column takes you to the last reply in a thread. Please change this to take us instead to the Last UNREAD reply. Many forums have this feature and it is much easier to keep track of rather than having to wade through posts you may or may not have read trying to look for where you left off.
Or keep the "go to last post" and add a small icon on the right of the thread to take you to the "Latest UNREAD Reply." Of course, this means that it will be based off a user's persistent cookies, so those who sign in and out constantly would not be able to use this feature when starting a new session, but would be able to use it while their session was alive.