The multi-user system seems pretty optional to me. I've got a XP home laptop, and aside from every once in a while seeing a reference to my user name, never deal with logging in or users. This day in age having users and permissions is a necessity for almost all computers that aren't used soley by one power user at all times.

On the family desktop, the users allow everyone to keep running their programs while someone else uses it. I never have to close my 50 windows that are open, i just switch users. There aren't any permissions associated with users, so everyone can still read everyones files.

In a corporate world, logging in and file permissions are an absoulte necessity.

Matthew