Desktop rebuild

[Derrick Ryalls]

I have a laptop that I am currently updating world to the latest from
the v6 branch, once that is done I want to completely start fresh with
the GUI.  Right now I have gnome in a mostly working state, a mostly
out of date KDE and a bunch of other random crud I have installed over
the last 16 months or so.  Instead of trying to use portupgrade and
have it fail out/fix/restart, I was thinking life would be easier if I
just removed anything graphical and start that from scratch.  This way
all my settings/data remain intact and I can just do a pkg install the
new stuff.

Is anyone aware of a quick/safe way of blowing away nearly all
installed apps as such to start from near scratch.  I do use bash and
probably a couple other non-GUI installs, so I didn't necessarily want
to kill _all_ installed ports/pkgs but I might be willing to do that
if needed.

Any thought on the best way to approach this?