This is how I use Ubuntu… if you mind?
Bépo (french Dvorak) is not an available keyboard layout in the Graphical installation. This is a pity. But, once installed,to switch to a Bépo keyboard layout:
sudo dpkg-reconfigure keyboard-configuration
Firefox and Thunderbird are replaced by Iceweasel and Icedove. But it's the same piece of software. If you already have a firefox session saved in your home folder, it will find it and all your settings will be available in Iceweasel. For Thunderbird, you'll needd to rename the ~/.thunderbird folder to ~/.icedove before starting it for the first time.
To get the latest Firefox on your system, here's the way to go: http://crunchbang.org/forums/viewtopic.php?id=27526 The trick is to change the /etc/apt/preferences file.
Scanning software not installed by default: Choose Xsane or Simple-scan
Useful resource for tweaking: http://www.webupd8.org/2012/04/things-to-tweak-after-installing-ubuntu.html
Some tweaking tools to try (haven't really found one that I'm happy with):