If you’ve been missing system files (e.g. plist files) in your Spotlight results or Finder searches, you need to follow this tip over at TidBits:
When you choose Other, you get a dialog listing all the kinds of metadata the Spotlight index knows about. You can just pick one to use it; you can also select a checkbox to specify that that option should appear in the menu from now on, so you don’t have to pass through the Other dialog to access it. I recommend that you immediately check two items that I think you’ll be using quite a lot:
System files. When set to Include, files are sought even in special locations such as /Library/Caches and ~/Library/Preferences. For example, if you search on “com.apple” you won’t find much, but if you include system files, you’ll find hundreds of preference files.
Spotlight items. When set to Include, searches are expanded beyond files and folders to include other sorts of entities, such as iCal events, Safari history items, and preference panes.
A huge power user tip: When you summon the Finder search window with Command-Option-Space, or from the Spotlight menu, Spotlight items is set to Include. When you summon the Finder search window with Command-F or by typing in a Finder window’s search field, Spotlight items is not set to Include. This is actually quite brilliant. Spotlight is making a very reasonable distinction and assumption here: if you started in the Finder, you probably just want to look for files and folders, but if you summoned the search window in a more global way, you probably want to look at all kinds of entities. Of course you can always summon a Criteria Bar and change the setting if the initial default isn’t what you intended.
Good search means a lean, clean system…