Command + Tab not switching between spaces

Hello all,

I'm having an issue with Command + Tab. Currently, this shortcut will only cycle through apps that are on the same desktop. I am unable to Command + Tab into an application that lives on another space.

For example, if Space 1 has both Google Chrome and iTunes and Space 2 has Finder, I am unable to Command Tab from Chrome to Finder (Space 1 to Space 2), but Command + Tab works from Chrome to iTunes (both on Space 1.)

What I've tried:

1. I tried Command + Tab on a guest account. It works correctly. This implies that there's something in my user settings/files that is causing the issue.
2. I have repaired my disk and my permissions via disk utility
3. I have tried the killall Dock as well as killall -9 Dock

Any ideas? This is driving me crazy!