To begin with I recommend looking at a LiveCD.
There are two worth taking an immediate look at and both use the GNOME Desktop Environment being Linux Mint 6 and Ubuntu 9.04 and both are very easy to use.
Linux is now in a position of offering a viable alternative to proprietary platforms and more than capable of offering a full desktop experience.
Install or RUN IT LIVE !
Linux Mint 6 Release notes
http://www.linuxmint.com/rel_felicia.php
Ubuntu 9.04 Release notes
https://wiki.ubuntu.com/JauntyJackalope/TechnicalOverview
Linux Mint 6 Download
http://www.linuxmint.com/edition.php?id=31
Ubuntu 9.04 Download
http://www.ubuntu.com/getubuntu/download
If you like either of them
Linux Mint 6 installation tutorial
http://www.howtoforge.com/the-perfect-desktop-linux-mint-6-felicia
Ubuntu 8.10 installation tutorial (also applies to Ubuntu 9.04)
http://www.howtoforge.com/the-perfect-desktop-ubuntu-8.10
You download the ISO. image of either Linux Mint 6 or Ubuntu 9.04 then you need to create a Bootable CD from the ISO. This can easily be done using Nero Burning ROM or similar software. Linux Mint 6 and Ubuntu 9.04 can also be run straight from the LiveCD you have created without touching your Hard Drive.
Screenshot of my custom LiveDVD of Mint 6 running Beryl 0.2.1
http://s266.photobucket.com/albums/ii256/Linux_Ubuntu_geek/?action=view¤t=Screenshot-1.png
Screenshot of my custom LiveDVD of Ubuntu 9.04 running Beryl 0.2.1
http://s266.photobucket.com/albums/ii256/Linux_Ubuntu_geek/?action=view¤t=Screenshot.png
Remember you can RUN IT LIVE !
LUg.