Ubuntu Linux is a fake distro. It is legal to still open source software and rename it since it's open source. But doesn't not mean that it's a good thing. Ubuntu is packages taken from Debian Linux and renamed with the Ubuntu name at the end. Of course most Ubuntu people are newbies and will deny this but all patches, bug reports and so on from Ubuntu are lifted directly from Debian. Even the change logs are Debian. You should keep this in mind. If you use a clone or hack you will get second hand support. If you want to use a Debian based distro I would suggest that you use Debian and give them the credit they deserve.
Mint Linux is a bit better then Ubuntu as they are not trying to take Debian packages and rename them to take the credit. Mint actually says it's based on Debian. However again if you want Debian just get Debian.
PCLinuxOS is a Mandriva hack. If you want Mandriva just go to the Mandriva website and get the real thing.
I myself Have created my own Original Linux Distro called Myah OS. You can try it out at http://myah.org But I will try and give you some unbiased help here not just push my own. So here is a list of Real distros that I would suggest for a Linux newbie that look good and work well to.
Suse is an origin professional Linux. It's free and looks good and is easy to use. I actually payed for this Linux before and was happy to do so. It is worth it. And it's free for those who don't want to pay. The free version is Open Suse. This is not some hack they are owned by Novell and are currently writing the radeonhd driver for ATI.
Mandriva is also a professional Linux distro. It used to be called Mandrake until they purchased Conectiva or something. It also looks very good and is Real no hack Linux.
Fedora is the free version of Red Hat. There are many clone of this since Red Hat is a major company. I don't like this one that much myself as I would go with one of the above. But it's still a solid Linux.
Debian is not a professional one like the above but is still probably one of the best Linux out there. It will work on any hardware and is very well supported. Which is why Ubuntu likes to take the credit for what they do. But I would not recommend this for a beginner. As I would try one of the top 2.
Slackware is the oldest running Linux distro. It has been around longer then all the others. It's also Totally Original. Slackware to me is pure Linux not extras just the basics. I would not recommend this for a Linux newbie. As it is more with the command line and has less system tools. Again it's pure Linux so it's keeping it real.
Gentoo is another with a huge community. It's totally original and is made more for the hardcore Linux user. You can build a complete system from the ground up. I would not recommend this for a newbie.
Oh and of course Myah OS lol. It's mine since I'm the developer. But compared to the above it's very small time and just getting started.
Please don't go with some hacked cheat of Linux. Give credit to the real developers and also you will get better support since your going to the source.