Apple has released a small update to iTunes, bumping it to version 11.0.4, and includes a fix for an issue that caused iTunes to quit if the user switched between wired and wireless syncing. The release notes say:
This update fixes a problem that may that my cause iTunes to quit if you switch between wired and wireless syncing and addresses an issue that may require you to log into the iTunes Store repeatedly.
The update is currently available through the Mac App Store, so go ahead and grab yourselves a copy, and let us know in the comments if it fixes your issues or if you happen to notice anything new.
Thanks to Keith for the tip!