In the sidebar of the Finder is a section called SEARCH FOR that contains searches for files from Today, Yesterday, Past Week, All Images, All Movies, and All Documents. You can open up your Finder Preferences to indicate which of these you want to show or not.

Turns out there are additional search options you can add to the sidebar in the Finder. They are:

All Applications
All Downloadds
All Music
All PDF Documents
All Presentations

If you want to add any of these, here is the process (this worked on my Mac using Leopard, unclear if this works on previous versions of OS X).

- Open a Finder window and navigate to the /System/Library/CoreServices directory on your hard drive (not in your user directory).

- Find the file called Finder, right-click on it and select Show Package Contents.

- This will open a new Finder window, showing a directory called Contents. Navigate to Contents/Resources/CannedSearches and you will see the new searches (and the old ones) that are available:



- Copy the search you want to add to the Desktop.

- From the desktop, right-click on the search you just copied over and select Show Package Contents.

- Again this will open a new Finder window. Click on the file called search.savedSearch and rename it. The name you enter here will show up in the sidebar of the Finder, so pick something appropriate like "All PDF Docs" if you are copying the "All PDF Documents" search.

- Once it is renamed, copy this file to the SEARCH FOR section of the Finder sidebar.

Once it is there, you can click on it and the appropriate files will be shown.