I didn't bother to install it, but reading the intro, KeyLaunch (
http://software.xfx.net/utilities/kl/ ) has a nice feature for non-techies:
You can either select the file types manually or simply drag and drop a file of the type you want to select into the File Types pane and KeyLaunch will select its type for you.
So if you want KeyLaunch to search for Adobe Acrobat files you don't have to know that these files have a .pdf extension... simply drop an Acrobat Reader document onto the File Types pane and KeyLaunch will recognize the dropped file type automatically.
Now I don't need this but it may be a nice way for general users to set up Search modifiers?