Ubuntu – Upgrade manager wants me to do a partial upgrade

Review your software sources, and remove any unused or outdated repositories.

Try one (or more) of these:

(remove unmet dependencies)
sudo apt-get -f install

(remove .deb archives from packages no longer installed)
sudo apt-get autoclean

(clear files from Aptitude cache: /var/cache/apt/archives )
sudo apt-get clean

Post the output of an update & upgrade:

sudo apt-get update && sudo apt-get upgrade

UPDATED:

Your active sources should (most likely) not include the 'backport' elements:

This is from my setup: (edited to 'GB', instead 'NZ')

(snip)
## Uncomment the following two lines to add software from the 'backports'
## repository.
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
# deb http://gb.archive.ubuntu.com/ubuntu/ maverick-backports main restricted universe multiverse
# deb-src http://gb.archive.ubuntu.com/ubuntu/ maverick-backports main restricted universe multiverse

Whereas your 'sources' appear to be: (or equiv.)

deb http://gb.archive.ubuntu.com/ubuntu/ oneiric-backports main restricted universe multiverse

These should also NOT say 'oneiric-backports' !?

Yes, do try and run

sudo apt-get install -f

From the --help usage text we find

-f  Attempt to correct a system with broken dependencies in place

You can get to this by using

apt-get install --help

Another good way to read up on usage is with man pages. The man page for apt-get states

-f, --fix-broken
       Fix; attempt to correct a system with broken dependencies in place.
       This option, when used with install/remove, can omit any packages
       to permit APT to deduce a likely solution. If packages are
       specified, these have to completely correct the problem. The option
       is sometimes necessary when running APT for the first time; APT
       itself does not allow broken package dependencies to exist on a
       system. It is possible that a system's dependency structure can be
       so corrupt as to require manual intervention (which usually means
       using dselect(1) or dpkg --remove to eliminate some of the
       offending packages). Use of this option together with -m may
       produce an error in some situations. Configuration Item:
       APT::Get::Fix-Broken.

There's nothing wrong with running the partial upgrade, incidentally, it generally fixes the problems in the package manner. Please let me know if you continue having these problems afterward. Best regards