How many run levels do you _need_?  One.  Single-user.  You can do the
rest from there.

How many run levels would I use, if I had them?  Five or six, at least.
I might add others later.

How many run levels should be available, for people who may have special
requirements?  Plenty.

Show of hands from everyone actually using files over 2 gigabytes on a daily
basis.  :)

-s