LinuxMint is a Linux flavour based off Ubuntu. Here I was, thinking that Ubuntu offers the best-looking, most polished end-user experience... and then I stumble upon the LinuxMint project. All I can say is, WOW! From boot to shutdown, I was impressed. Check it out for yourself:
http://linuxmint.com/
P.S. Keep in mind that you can always try LinuxMint or Ubuntu on your computer without touching any data on it (Linux will load and run entirely off the CD).