Open Synaptic. Click on File, Save Markings. Check the box at the bottom to
save Full State. Give the file a name and put it in a place where you can
access it on another computer. Dropbox or a usb key works nicely.

To use it, Open Synaptic on the other computer. Click on Read Markings.
Locate the file. Then Apply the changes.

There are limitations. It only will do files in the standard repositories.
Outside sources will not work, unless you add the additional sources first.
If you switch distributions it will not provide all of the packages as
Ubuntu has more packages than many distros. Also it may install things that
you do not want or that are not available on another distro. The farther
that you deviate from the Ubuntu tree the more problems you are likely to
have. Even Mint can give you problems, but they are likely to be minor.
Debian is likely to be more problematic where even things like Firefox are
not in the repositories. Instead you will have Ice Weasel.

That list is long, very long. Is there a way to get a list of just the programs
or downloads (such as xyz.pdf) that I have installed or DLed myself say via
Synaptic or Ubuntu Software Center.

I could do this myself but should I forgot to do the note taking on paper or on
a file in my backups that program or DL will be missing, plus I'm just plan lazy
and after all this is a computer, how about it doing that drudgery for me.

While we are on this subject, it would be nice if all the configuration
modifications made were documented somewhere.

Both of these wishes probably don't exist, at least not in the fashion I'm
talking about but sure would make a nice project for a Ubuntu whiz-kid.

Packages are not the same as applications.The list is of all packages and
this includes libraries and dependencies, making the list rather long, as
you found out. Those bits and pieces need to be installed to make the
applications work which is why they are included in the list. It is just a
text file. You can edit it by hand. It is tedious, but as long as you save
it as text file it is still usable. I know of no easy way to make a list of
just installed applications without all of the supporting cast.

You should be able to simply delete anything that starts 'lib......'
from the list - they're just libraries which should be pulled in as
needed, either as part of the base install or required dependencies for
any packages you install later. You should also be able to delete
anything that starts 'linux......' or 'openoffice......' as these would
be installed as part of the base system. This should vastly reduce the
number of entries and make further editing of the list a little easier.

There is no simple, single line terminal command to get a list of just
the parent packages without their dependencies. It should be possible
to write a script to do it for you - it would be a fairly tedious and
messy script based on the fact that the command 'dpkg -p
| grep -i depends' gives a list of all dependencies for the package -
but I'm afraid my bash-fu is weak at the moment :-)