Yes, this is a case where the proper pluralization is "mediums", and not "media".
1. You could just set a sort of heuristic lower threshold on how much attention you're willing to give to the choice of a given piece of software. Basically, as you consider what GUI environment to use (KDE, GNOME, XFCE, IceWM, Fluxbox, WindowMaker, Sawfish, Enlightenment, et cetera), you just look into them until you get tired of looking, then choose from among those you've already examined. If you later find out that there are some things that annoy you, you can revisit the issue.
That's really the practical way to handle it, and it's pretty much what everyone does. Nobody (sane) actually examines critically every single window manager and self-proclaimed "desktop environment" in great depth, seeking out every obscure little side-project in the world, before making a decision. If you really [b]really[/b] don't want to think about it, just pick a major distro and use the default. That's usually the best option for someone brand spanking new to Linux. Eventually, you'll start wanting something more specifically suited to your own proclivities, and at that point you'll be grateful for the additional choices.
If you're at all like me, you'll start branching out into other options, testing them against your preferences, quite quickly. Some people just stick to their first as their permanent favorite, however, and they're welcome to it.
I've found a happy sort of middle ground between ultimate configurability, truly lean and mean, and productivity enhancing. I've pretty much abandoned any pretense of "desktop environment" integration, however. That's me. You don't have to make the same choices.
If you're a rank newbie, I recommend you make as few choices as possible at first, but let your comfort level guide you. That's really the trick that some habitual MS Windows users never quite grasp when they take their first steps into the land of open source software: they see that there are millions of choices, and they somehow think they [b]have to make a choice from all those options[/b]. They don't. Go with whatever's initially convenient, and don't think about it too much.
2. You could pick a smaller software ecosystem, to help narrow things down comfortably. For instance, if you just take Ubuntu as the Linux poster boy, as one choice, and add to that the three primary *BSD OSes (FreeBSD, NetBSD, and OpenBSD), then you have a nice spread of options laid out before you. Compare them with one another, make a decision based on their relative merits, and go with a default desktop install. Voila, you're in business.
Then, as before (in the first idea for how to handle it), branch out into other options if and when you find that you're curious and perhaps in search of something that more closely suits your personal proclivities.
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I, personally, just kinda jumped in with a Linux distribution that was available and convenient. I bounced around through a few, finding things to like and dislike about each of them. Ultimately, I was introduced to Debian by some people I knew who figured I'd probably like it, and it turned out I really, really did. Once I got the hang of APT, I figured out that to really [b]really[/b] make things work best for me, I could just do a minimal install and use APT to build up from that to a fully functional desktop/workstation system that suited me exactly. This all happened before Ubuntu was even available.
While I've played around with other distributions since then (including Ubuntu), I've never found another Linux distro that I liked more than Debian. It's among the most stable, among the most secure by default, among the most easily managed via the standard toolsets, among the most standardized at its operational environment foundation, and the one operating system with the single most extensive software archives, period. In fact, the next-biggest official software archive for any major Linux distribution is less than one tenth the size.
Then . . . I discovered FreeBSD. It's more stable, more secure by default, just as easy to manage for a skilled sysadmin, more configurable, easier to configure in some surprising ways than any Linux distro I've ever touched (though plagued by the occasional counterintuitive default for "historical reasons"), and has damn near as much software in its archives as Debian. That is [b]very[/b] hard to beat.
That may or may not provide you with some ideas of what others may find useful for their own progression through the free unix learning curve. I offer it in case it might help provide some idea of how one might more easily just go with the flow. Don't think of this as something you have to get Exactly Right, Right Now; just take it a step at a time, and have fun with it.
The choices aren't all there because you have to make them all right this instant. They're there because eventually, if you like what you're getting yourself into, you'll almost certainly want to explore them as you get comfortable with what you've already experienced.