Here is a short video showing how to add short cut folders to your side bar in OS X. The video shows me adding the folder ebooks and then removing the folder (it disappears in a puff of smoke). I use this to keep project files in easy reach. Since it is simple to add and remove folder or other items, the side bar can function as a work area to keep track of things you need fast access to.
One benefit of this is that the items will show up when you do a "Save As" or "File Open" as well. This little trick saves me a tremendous amount of time because I can quickly reconfigure things for whatever I’m working on. When I’m busy with a particular client, I’ll put their folder in the sidebar. When I’m writing for the 501 websites, I’ll put my "content" folder in the sidebar, when I’m programming my "workspace" folder goes in the sidebar.
I think you can do something similar with windows by putting shortcut folders on your desktop.
(This is my first experiment with adding video. Let me know what you think in the comments. Especially let me know if it doesn’t play on your computer.)