In a paperless office, the untidiness is much harder to spot!
I have a pile of about 6 bits of paper that are pending.. mainly bills or things that cannot be auctioned yet for some reason. All paper is either filed, shredded or recycled immediately after being dealt with so there is never much of a build up.
However I always archive email, never delete. I've never bothered with email categories as searching+starring is normally enough to make anything I need to find findable.