There is no "real" linux.
Linux simply refers to the core component of the operating system, the kernel. This is the fundamental difference between Windows and Linux. Windows includes the kernel and hundreds of other tools, a Graphical User Interface, drivers, fonts, various services and systems. Linux includes the kernel. If you want something other than some status messages and then a flashing prompt on the screen, you need to get other programs.
Which is where distributions (aka. distros) come in, and is the reason there are so many of them. The first thing you'll learn about linux is that for any one thing you want to do there are 2 or 3 applications that have been written to do it, and for all 3 of them there are people who will explain, at length, why the one they use is the best.
Consequently there are a hell of a lot of options when putting together a fully functional GUI linux system, leading to many different distros.
At the complete newbie end of the scale there are distributions such as
Xandros and
Linspire (previously known as Lindows). The sole aim of these distributions is to replicate the Windows experience under Linux, keeping the naming conventions the same (Drive C instead of /dev/hda1 etc). They generally come packaged with several applications.
Moving on there are the likes of
Mandrake. Distros such as this one will still provide you with a fully functional GUI desktop, but they don't "Windowsify" it. You will have to learn the Linux naming conventions and filesystem, among other things. They will still autodetect most common hardware during the install, but you will be given options on what to do with it. You also have many more options about what applications to install, down to chosing which GUI to use and so on.
Getting towards the power user end are distributions such as
Suse and
Debian. These are distributions designed for users who are experienced and know what they want. Consequently, an installation of one of these distros may not even give you a GUI by default. The idea is for you to decide what you want and only what you want.
Finally at the top end, in terms of required understanding, are distributions such as
Gentoo. Anything you want in Gentoo, you compile it yourself, including the kernel if you want. The Gentoo docs will get you started with a basic system, but it's up to you from there.
No doubt I've missed out things and will be corrected, but that's the basic view as I see it