This might not work for everybody, but... I noticed that right before the sync chokes, iTunes is processing photos. Likely, I figured, there's a discrepancy in what iTunes thinks is there and what actually is. An effective way to solve this issue (without obvious help from Apple / iTunes / iOS) is to remove the 'iPod Photo Cache' folder that's within the iPhoto Library on your synching system.
So, on my Mac, I navigated to my Pictures folder, right-clicked (or Control-clicked) the 'iPhoto Library' icon, selected 'Show Package Contents,' then scrolled until I saw the 'iPod Photo Cache' folder, selected that folder and deleted it. I then restarted iTunes to re-initiate a sync.
That seemed to resolve the "[n] tems could not be synced. See iTunes for more information." problem for me (which was occurring on my iPad 2 and iPhone 4S equally). Might work for you, too.