PC/OS: Insert CD, use desktop
PC/OS aims to be an easy-to-use Linux distribution right out of the box. Being Ubuntu-based, it has a head start on being user-friendly, but PC/OS goes above and beyond Ubuntu's measures to ensure ease of use by having common third-party non-GPL software included in the install.
The PC/OS distribution comes in several different flavors: OpenServer, OpenWorkstation, and OpenDesktop, all of which weigh in at around 700MB and fit on one CD. Included with the server edition are Webmin and other GUI utilities to make various server operations easier. The workstation edition includes multimedia production tools, software development tools, and office tools. I tested the desktop edition, which focuses on everyday use.
Like many distributions, PC/OS boots into a live CD which you can use without installation, or you can install it to your hard drive at boot time. The install is simple. It asks you which user name and password to use.