BashStyle-NG is a graphical Tool for changing the look and feel for Bash, Readline, Nano and Vim.
There are tools available to allow anyone to create and distribute a completely customized Ubuntu Based distribution using the Gnome Desktop. Many Kubuntu users would like to do the same thing but such tools are not fully compatible with KDE and the Kiosk tool does not change or remove all of the Kubuntu defaults so that a program like Remastersys can create a customized ISO with the defined changes.
If you like to customize your applications' appearance, then Firefox themes probably haven't impressed you. Although there are hundreds of themes available, typically all they allow users to do is change the icons and background color of your browser -- not too exciting. Personas for Firefox offers a new way to customize the browser.
SSH is great. There is so many thing you can do with it other than just a remote secure shell like X forwarding, port forwarding, authenticate using a private/public key, compress the transmitted stream....
Best Greasemonkey and Stylish scripts (both are Firefox extensions).
One of the great things about using open source software is the frequency with which bugs are fixed, security holes are patched, and new features are added. Ubuntu includes a very convenient update manager but constantly upgrading your system can be a burden. This guide will explain howto customize the manager to run less often, or automatically install updates.
Many people want to customize their login screens. Where I work we customize the Novell Login screens and put a default Legal Notice for all the users. It would be nice to customize the login and shutdown screens for UBUNTU to display custom graphics. Here are the instructions on how to customize the GNOME login screen to display legal notices before users can.
Many customers, particularly those who are security conscious or those who have public terminals like to display a legal notice before users can login.
I'm feeling spoiled. After years of enduring one questionable Microsoft UI decision after another, I'm having a blast tweaking and re-skinning gnome under Ubuntu 7.10 “Gutsy Gibbon.” To be sure, it's a buggy process. I've crashed X a few times and left myself with a hung shell on more than one occasion (had to jump out to the terminal and do a forced shutdown via CTRL-ALT-DEL). And I've also had my share of application weirdness (OpenOffice tends to choke on certain “incomplete” themes).
This a great how-to that gives you step by step instructions on how to create a custom Ubuntu live disc (of any flavour). The artical is a bit old (it refers to a flight cd for dapper) but the method is still the same for the latest release.