Howtoforge posted a tutorial about setting up Linux Mint 12 as Linux desktop replacement

This tutorial shows how you can set up a Linux Mint 12 (Lisa) desktop that is a full-fledged replacement for a Windows desktop, i.e. that has all the software that people need to do the things they do on their Windows desktops. The advantages are clear: you get a secure system without DRM restrictions that works even on old hardware, and the best thing is: all software comes free of charge. Linux Mint 12 is a Linux distribution based on Ubuntu that has lots of packages in its repositories (like multimedia codecs, Adobe Flash, Adobe Reader, Skype, Google Earth, etc.) that are relatively hard to install on other distributions; it therefore provides a user-friendly desktop experience even for Linux newbies.

  The Perfect Desktop - Linux Mint 12 (Lisa)