CH just wiped my computer, reinstalled XP, and upgraded me from Office 2003 to 2007.
Enter the Ribbon. Maybe it's just an old-dog-new-trick issue -- I'm willing to give it some time -- but my first reaction is pure disgust. Give me my menus and my carefully customized toolbars back! Don't make me click twice now to get to the functions I use all the time.
OK, deep breath. Maybe I can rebuild my own custom default menu... I'll give it a try.