I'm having issues with mouse movement. It's very jerky, especially when moving diagonally. The menu mouse works fine, it's the cursor while in first-person that's really jerky. Stuff I've tried:

-Disabling VSync
-Disabling Mouse Acceleration
-Disabling Gamepad
-Changing X/Y Mouse Heading

The problem actually fixes itself when I'm playing in windowed mode, but I'd like to be able to play in fullscreen. Anyone have any suggestions?

Try that: http://www.nexusmods.com/skyrim/mods/36177/?