iPhoto needs to be able to do subcategories (sub-albums). I have many albums related to family events, it would be great to be able to hide them when working on an album related to my Travel photos. So I could have 4 or 5 main Albums (Family, Friends, Travel, Work) and then have albums under those (under Family, have Christmas 2002, Thanksgiving 2003, Reunion 2003, Laura’s Birthday 2004, etc…).