Another Linux distribution that has appeal is Linux Mint. This one comes close to having the same look and feel of using Windows... the menu and start button being similar. It is derived from Debian/Ubuntu, and differs in release dates... Ubuntu is every six months, and mint isn't. I have it set to dual boot with Windows 7, but it can be installed on older machines by itself or in dual boot... needs atleast 512 megabytes of RAM and a one gigahertz processor.... the OS flies on a dual core machine and will run slower on a lessor machine.
http://www.linuxmint.com/index.php