Ok, so we know Windows Explorer doesn’t display the size of Folders. I am not really concerned about the size of a particular folder, unless I am really running out of space on the disk. Discovered this open source app, via Digg.com, – http://foldersize.sourceforge.net/ that will display the size of Folders as well in Windows Explorer. Seems useful, if someone is really interesting in checking the sizes of every folder.
I personally prefer to use JDiskReport – This is a free download, and also provides nice graphical analyses of the disk usage. Some screenshots of the kind of analyses – http://www.jgoodies.com/freeware/jdiskreport/screenshots.html