CNET's Worker's Edge blog offers up a way to customise the default locations for saving or opening files in Windows XP by putting shortcuts to your favourite folders in common dialogs via XP's Places Bar.
You can use Microsoft's own Tweak UI utility in PowerToys for XP to do this. Or to do it manually, hit Start > Run and type:
gpedit.msc, and press Enter to open the Group Policy applet. Navigate in the left pane to User Configuration > Administrative Templates > Windows Components > Windows Explorer > Common Open File Dialog. Double-click Items displayed in Places Bar in the right pane, check Enabled in the resulting dialog box, and enter the folder paths in the five text fields below it.
You must enter five locations to avoid having empty default locations created, and you'll need to follow his directions for specifying the path.
He also explains how to do a similar thing in Vista using Favorite Links.
There's certainly a few ways to shortcut to your favourite locations in Windows - I use FileBox eXtender to give me one click access to my frequently used folders. Got a favourite shortcut? Please share in comments.
Place shortcuts to your favorite folders in Windows' common dialogs [CNET Worker's Edge]