what version of Linux is best and why?

Take a look at Linux Mint 5 (Main Edition) its easy to install easy to use and has much of the software you are likely to need preinstalled.

Linux Mint 5 Release notes

http://www.linuxmint.com/rel_elyssa.php

Linux Mint 5 Download

http://www.linuxmint.com/edition.php?id=25

Linux Mint 5 installation tutorial

http://www.howtoforge.com/the-perfect-desktop-linu...

You download the ISO. image of Linux Mint 5 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 5 can also be run straight from the LiveCD you have created without touching your Hard Drive.

LUg.

Ubuntu Linux is by far the easiest version for the casual user to install and adapt to. It has the widest range of apps, most user-friendly design, and requires little to no knowledge of software modification. You can even use a program called Wine to import some of your windows apps!