UPDATE: Please go here for the new GUI version of this script that also includes some extra items.
I was actually going to write an entry this morning about packages to purge or install upon a fresh Ubuntu build but Ubuntu Linux Help beat me to the punch. It's a great article and well worth the read. I've modified the list slightly and created a bash script to execute it. The file is here. Just extract it ( tar xvf ubuntuTaks.sh.tar.gz ) make sure it's executable ( chmod +x ubuntuTasks.sh ) and execute it using ./ubuntuTasks.sh
Below is the code inside in case you want to just copy and paste it into your own file:

#!/bin/bash

sudo apt-get remove --purge mono-common libmono0
sudo aptitude install sbackup
sudo aptitude install ubuntu-restricted-extras && sudo aptitude install w32codecs
sudo apt-get install msttcorefonts && sudo fc-cache -fv
sudo aptitude install vlc
sudo aptitude install k3b
sudo perl -pi -w -e 's/\; default-sample-channels \= 2/default-sample-channels \= 6/g;' /etc/pulse/daemon.conf

As always, this code comes with no warranties. I have run it on my system and all is well.