Although my reply is a little late, I felt I try to give you advice.
First of all, congratulations on your deciding to switch to a real operating system!
I will go ahead an clarify a few misconceptions as to what Linux is an what it is not:
1) Linux is just an OS kernel, not a complete operating system in the general sense
2) Different Linux distributions (abbr. distros) such as Debian, Gentoo, Archlinux etc. etc. etc. basically use the Linux kernel and build an OS environment around it
3) This environment typically consists of a virtual terminal, shell, and in many cases a graphical desktop environment (KDE and GNOME are popular choices)
4) Most distributions come with their own package manager, which allows you to easily search software dependency trees, and install software packages without having to resolve those dependencies yourself, e.g., "apt-get" in Debian/Ubuntu, "yum" in Red Hat-based distros, "pacman" in ArchLinux, "emerge" in Gentoo... the list is vast.
Now, wanting to learn Linux and using Linux are two different things. What I mean is, most "newbies" decide to use Ubuntu because it is the "newbie friendly" Linux operating system. The problem with this approach, however, is you are never actually exposed to the true power of Linux. If you ask an avid Ubuntu user to install a package from src in a tar.gz, they would be lost. They become dependent on the playground setup by Ubuntu' devs.
I myself started out using Red Hat w/GNOME, and did not really learn Linux until I decided to use Gentoo, which is almost like building a Linux distro from scratch (there is actually a Linux from Scratch distro to effectively build your own distro!)
Now, while Gentoo is great, it is also not the most usable OS, especially for newbies. In many cases, it would probably put off a new user from using it, since it is hard to use, and you have to compile everything from source. In fact you would probably have to install it several times before you even get something working, and then one command later you will likely blow up your OS and have to reinstall all over again!
I suggest Debian Linux, ArchLinux or CentOS. Debian is actually the distro that Ubuntu is based off of, without having the Ubuntu fuzz thrown in. ArchLinux is a great operating system to learn on, has a very good community and support both binary and source compilations from their package manager repos. CentOS is Red Hat based, and is also a very nice OS.
I would go ahead and do a little research on these different distros, check out their install guides, and see which one you like. Don't let the fancy GUI get in the way of what you can do with Linux. The command line is the most powerful tool you'll have.
Hopefully you don't TL; DR