[plug] Removing old package dependencies with apt/dpkg [derived from: apt-get sources.list]

[ryan at is.as.geeky.as]

In reference to all this apt talk, I think I vaguely recall someone telling
me this following feature question doesn't exists and that it would be
'nice' to have ... I could be mistaken though:

The question:
=============
Is there a way to 'apt-get remove xyz' and have it remove all dependant
packages that are no longer needed or dpkg -r/--purge with the same effect -
ie. remove the packages that were installed along with that package xyz as
dependencies if they are no longer depended upon by any other package?

If not then I'm sure a few joint efforts between apt and dpkg in a shell
script could achieve something of the sort?

Ryan