I just synced my iPhone to my Mac and saw that it has 850MB of "Other". What items class as "Other" in storage? I have 6GB of audio, 1.6GB of photos, 1GB apps, 3.2MB books, and then 850MB of Other. My iPhone is Jailbroken so I know that will be where some of the space has gone. In fact, halfway through this I remembered the saved apps on Installous, so I just went back to delete them all and now I'm down to 610MB, so that's still a lot.