No offense to the OP (well, maybe a little), but this has got to be the most frequently asked question across Mac forums. And I imagine most searched (at least by conscientious forum members).
Maybe Apple ought to redefine that "other" category and give us all a break. It truly seems a disservice to users.
And I haven't been tracking the results of these posts about mysteriously disappearing storage, but there must be some problem besides a user being unable to identify what's stored on their drives. Anyone know what's causing this so often?