I'm sure all the programmers here have a File Diff app/utility already, but today I decided I'd see if anything cross platform was available. I work on Windows, OS X, and Linux and use Sublime Text 2 as my editor so the first thing I looked for was a plugin for it. Nothing jumped out at me so I looked a little more and came upon kDiff3. Binaries are available for all my platforms complete with installers and it's FREE. Check it out if you're in need of such a tool.