get list of config files (with aptitude) tha were manually changed

["A. F. Cano" <afc@shibaya.lonestar.org>]

I know that this is checked somehow as I have been asked which config
file to install or leave alone when upgrading various packages with
aptitude.

What I would like is a command line (not interactive) that would give
me a list of all the config files in all installed packages that were
modified from the original/default values.

I'm doing a new lenny install on a blank drive because I want a clean
slate and none of the disk corruption/missing files/old useless files
that have accumulated over multiple releases.  But I dread having to
re-configure every package manually or editing every config file
manually.  I have the cruft output (236119 lines!) but this includes
kernel source (for multiple versions), /home files (which I'm backing
up and restoring anyway and much much more that it's not realistic
to go through.

Are there some options to aptitude (or dkpg?) that would give me this
list of only the config files that were changed?  I've gone over the
aptitude reference manual but didn't see anything obvious.  Maybe
someone more experienced with aptitude can point me in the right
direction?

Thanks.

A.