I thoroughly recommend Linux Mint 9 Main Edition which is built upon Ubuntu 10.04 Its easy to install and easy to use plus it comes with much of the software you are likely to need preinstalled
Linux Mint 9 Download
http://www.linuxmint.com/edition.php?id=52
The Perfect Desktop - Linux Mint 9 (Isadora)
http://www.howtoforge.com/the-perfect-desktop-linux-mint-9-isadora
Linux Mint 9 User Guide Download pdf.
http://www.linuxmint.com/rel_isadora.php
You download the ISO. image of Linux Mint 9 then you need to create a Bootable LiveCD for installation
Linux Mint 9 can also be run direct from the LiveCD from Booting up without touching your Hard Drive
Also worth considering :
Linux Mint 9 LXDE
http://www.linuxmint.com/edition.php?id=60
http://linuxmint.com/rel_isadora_lxde.php
Fedora Remix (Fedora with elements of Linux Mint)
http://fcoremix.wordpress.com/2010/05/25/lucky-13/
http://iso.linux.hr/community-fedora-remix/
http://docs.fedoraproject.org/en-US/Fedora/13/html/User_Guide/
Ubuntu 10.04
http://www.ubuntu.com/desktop/get-ubuntu/download
http://www.howtoforge.com/the-perfect-desktop-ubuntu-10.04-lucid-lynx
http://ubuntuguide.org/wiki/Ubuntu:Lucid
Again Linux Mint 9, Fedora Remix and Ubuntu 10.04 can be run direct from the LiveCD/DVD without touching your Hard Drive
Also you can try out as many different Linux distros. as you like on LiveCD until you find the one thats right for you DISTROWATCH.COM gives full listings (second lists the major distributions)
http://distrowatch.com/
Major Linux Distributions
http://distrowatch.com/dwres.php?resource=major
LUg.