It is nearly impossible for someone else to suggest which Linux distro you should use. The freedom and flexibility which is part of the Linux culture means each distro has popularity based on a preferred set of features, either missing ( for security reasons, to name but one reason ) or available e.g. buying support as and when you need it.

Here's the nice part about this - with a small amount of experience, after a couple of installations from 2-3 distributors, fiddling with whatever you can find, very soon one is able to make up their own mind. Before you start downloading many of the FREE distros, perhaps take a moment to read something about the various distros and decide on your own short-list :- http://distrowatch.com/index.php

Another method, might be to take an introductory course. The advantages of doing this are many, for example, one does NOT have to risk losing their own system, with experimentation. Rather join a class where people have the same questions and curiosity, and most likely will work through about 80-90 % of the decision-making process with you.

Knowledge is a Powerful thing !