Tiger: Change the Behaviour of Command-F in Mac OS X 10.4
by Kristian Andersen, MacXimus I/S
12th July 2005

Using Command-F or File > Find in the Finder loads up a Spotlight powered search dialog that is ready to use as is, or which can be populated with additional fields in order to run a query for a more focused search. If you use this feature often enough and have a fondness for using these extra parameters it can be a big hassle to add them in one-by-one every time you do a search.
Kristian Andersen steps in with a handy solution for us!

The image above shows the default search dialog, let's give this thing some more power.
To change the default behaviour of Command-F, do the following:
Browse to the following directory: /System/Library/CoreServices/Finder
Control-click “Finder” and "Show Package Contents". Replace the file noted below with the one provided in Kristian's pre-configured download, make a backup of the original file first by dragging it to the desktop.
Contents/Resources/default_smart.plist
You will be asked to confirm replacement and type in an administrator password.
Close the folder, open “Disk Utility” and repair permissions. Restart your computer, or log out of your account or just restart the Finder for the mod to take effect.
The next time you press Command-F your search window will look something like this:

Now, every time you use Command-F you will be able to specify file-names, contents, kind and visibility without having to change anything. Neat and handy!
The options can be changed further by modifying the .plist file itself.