Find In Files wasn't scanning one of the files in my project, - it would never find even the easiest matches (like the class name). I narrowed the issue down to a place in the code where it strips invalid characters from a string.
The exact character that is blocking Sublime from including the file in the find results appears as: 'SOH' in a square. This comes out to hex code '01', which is the Start of Heading character.
By the way, I ruled out the binary_file_patterns setting. When I remove the character, the file starts coming up in the search results as expected.
I'm on Windows 8 with Sublime Text 2 version 2.0.1 build 2217. I did buy the product a few months ago. This is the first time it has ever acted strange.
Hope you can get this fixed and it saves other people headaches in the future.