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 :-)