Clone and run this on a new EC2 instance (or any other ubuntu) running Ubuntu 12.04.2 LTS to configure both the machine and your individual development environment as follows:
cd $HOME
sudo apt-get install -y git-core
git clone https://github.com/Butterwell/ubuntu-setup.git
./ubuntu-setup/setup.sh And to install everything for some reasonable value of everything: ./ubuntu-setup/kitchen-sink.sh
See also http://github.com/Butterwell/ubuntu-dotfiles for more details.