Mac OS X has long had the Go menu in the Finder. Within it there has long been quick Finder access to folders. The shortcuts listed there have also been usable in Open/Save dialogs (with the exception that going to the Desktop in an Open/Save dialog is done with Command+D, not Command+Shift+D like is used in the Finder).
10.6 added the Documents folder to the Go menu. Oddly, though, its Command+Shift+O shortcut that could used in the Finder was not available in Open/Save dialogs. 10.7, though, corrects this and users can now use it to get to their Documents folder in any Open/Save dialog.
[crarko adds: I tested this, and it works as described.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20110721123200487