David already mentioned this, but I thought I'd mention it too. One of the guys at work wanted a utility that would display the size of a folder in Windows Explorer, so I did a little searching. I found Folder Size for Windows, a freeware utility that adds more columns to the Windows Explorer interface. The columns that can be added include:

  • Folder Size
  • Folder Size Sort (same as Folder Size but formatted to sort properly)
  • File Count
  • Folder Count
  • Sibling Count

As well as several other useful features. Check it out.