This is the most difficult question for ALL new linux users!!!
Why? Simple: because it depends on Your needs. What do You want from a distro?
Let's figure out some basic knowledge about distros...
1. Newcomer or easy 'linuxing' use Ubuntu, or it's derivatives: Kubuntu, Xubuntu, etc.
Also Linux Mint - based on Ubuntu.
Why? Because it has growing popularity, ease of use, easy solving problems by comunity.
*As You may know, the GNOME desktop environment is used in Ubuntu, the KDE is used in Kubuntu, the XFCE is used in Xubuntu. The base is the same, the desktop environment changes.
2. Mandriva - also easy, has free and money version, looks great, good for beginners too.
3.Fedora - the nowadays Redhat, I could say, well maintained.
4. Debian - base distribution for Ubuntu and other OS, has a strong support, very stable, has rarely releases because of it's strength and stability. Many updates between major stable distro release.
5.OpenSuse - wants ease in use, and nice configuring tools.
6. SLACKWARE and GENTOO are highly configurable, but may need some in-depth console knowledge.
7. PcLINUXOS, CentOS are also well-known, especially for server editions.
As a CONCLUSION - the above order is not a must, and it is NOT complete! You have to decide what You want. I recommend to search some sites like distrowatch.com and distromania.com and of course the each distribution website.
See here some pro's and con's:
http://distrowatch.com/dwres.php?resource=major
Anyway from start decide what You want (ease of use, lots of configurability, long term support, loads of applications, etc.).
Download some live-cd's from what You have decided, and boot from it to test.
I'd like to mention some artist-need distros, which have many tools and applications already installed useful for different type of artists: 64Studio, ArtistX, UbuntuStudio.
P.S. I always have a live (bootable) cd or memorystick with me for rescuing, in case my Win or other OS fails to work.
P.S.2. Hope not to be boring
🙂