The New Posts link is only bringing up 2 - 3 posts, even though the Welcome Back link shows I should have 55 new posts. Is this only happening with my computer?
The new posts search will show you the threads that have new posts in them. Inside of each thead there may be many new posts, so you just have to get in there and dig.
Also, don't forget the Quick Links tab in the second row of task bar buttons. Click on that and then on 'Today's Posts' in the dialog box. It lists all posts in the last 24 hours. However, as with the New Poststab, it lists only the latest post in a given Thread, so be sure to look backwards to make sure you've got'em all since your last visit.