Linux Mint is one of my favourite Linux distributions.
It’s easy to install (even easier to install than Windows 7!), it is based on Ubuntu Linux and it has everything most people want/need on their computer installed and ready to use (web browser, office suite, media codecs, browser plugins, etc.).
Linux Mint 9 XFCE Edition is now available as a free download.
The XFCE Edition of Linux Mint is more lightweight and less resource hungry than the Main Edition because it uses the XFCE Desktop Environment. It only requires 256 MB of RAM and 4GB of hard drive space to be installed, and is therefore ideal for older machines.
It’s easy to install Linux Mint 9 XFCE Edition alongside an existing Windows OS and choose between the two at the time of turning on your computer. On newer machines it is really, really quick.