I switched to Linux on my main laptop circa 2006. Going back to Winblows because some tech needs it to update firmware (I.e. my GFs insulin pump) is psychologically painful for me now.
Those new to Linux are going to want the easiest road in, which means easiest to install and best documented (officially and with other tech blogs and tutorials). I agree with the above that say Ubuntu (debian based) and Fedora (Red Hat based) are the most polished install experience and highest user base distributions (so most likely to have someone else run across and document a solution for your problem already). Unfortunately, tutorials for one do not always work for the other (and go out of date quickly, pay attention to how old it is!), so knowing whether this set of instructions applies to your install is half the battle!
The third major camp is Arch Linux. This is not designed for those new to Linux and can be challenging to install well. However, the Arch Wiki is fantastically documented, and sometimes contains tips, tricks, and solutions that might be applicable to debian or RH installs as well. But when I finally “graduated” to my own arch install from scratch, there was a huge sense of satisfaction and fine grained control over everything about my computing experience.
As to Desktop Environment, you’re looking for three factors: smoothness, size, and speed. Smoothness is does everything just work?!? Sticking with the default DE from your chosen distro usually gets you the smoothest experience, but the good news is trying out others is very easy and low risk! Size is memory footprint, which should not be an issue on F.w, but is something to think about when trying to put Linux on older machines with less than ~4GB ram. LXDE, Xfce are two common “light” desktops that work fairly well but not always the most smoothly in my experience. The last factor is speed, and again on machines with the power of the F.w speed differences are slight to unnoticeable between Gnome, KDE, Unity, etc “full featured DEs”.
The awesome thing about Linux is there is more than one way to do it and probably more than one piece of software to accomplish what you want. The bad news about Linux is there are so many names of competing, overlapping, and obsolete pieces of software to keep track of!?!
Have fun learning it, it’s a great hobby and skill to have!