I agree with everything Robin2 said down to Ubuntu as being the "best overall support" under Linux. You should give it a try! If your PC has a DVD drive you can try a Live DVD and see that everything works. I think part of the reason it's so "bloated' as compared with the slimmer distributions he mentions is that it includes a lot of hardware drivers and the like and also a ton of software (like libreoffice). All of your peripherals like webcam, sound card, wifi adapters, everything should "just work." Among the Linuxes, in terms of ease of use Ubuntu is the easiest.
He mentioned that you can run it from a USB flash drive. Here are the Instructions on the Ubuntu site, but, it might require entering your computer's "BIOS" configuration which you can enter from among some of the messages you first see when starting your computer ("Press F12 to...." -- well, you might have to press F12). Then you would find the boot options and allow it to boot from a USB drive. It might not "just boot" from the USB drive, even if you've set up the USB drive correctly.
If your PC has a DVD drive, to be perfectly honest the quickest, easiest, and most fail-safe way to try out Linux would be to order a LiveDVD which someone has burned. You can then just put it in the DVD drive and when you start your computer, pay attention to the option to start from it and select it. (Or it should do so automatically.)
This is what an Ubuntu desktop might look like around when it starts up:
As you can see, you would immediately know how to use it. There is a Firefox browser, you could open it and search for anything you needed to know. There are programs for handling office files (libreoffice) and everything is extremely intuitive . And as the first link to the LiveDVD explains, when you're ready to install it you can just double-click and have it install onto your computer.
However, if you already have a Windows installation and want to keep it, you will want to search for instructions such as this one on "dual booting" Windows and Ubuntu. The advantage of using the "Best-supported" Linux is that you can simply Google, e.g. "windows 10 ubuntu dual boot" and get extremely detailed instructions - and not just one or two. Here are some things you might want to do after installing Ubuntu. - install applications like Spotify and other things that aren't in the central repository (which you can think of like an 'app store.') Anything you want you can find and install easily!
Now, one thing to note is that you're now a Linux user! (This could be obvious, but when we spend so much time in web applications it's easy to forget...) You can't just install any old thing. If you had used Photoshop, well, now you need to use a Linux version. (Gimp). If you used Microsoft Word or Excel - well, now you need to use a Linux version of these tools. Linux is a great operating system but you will now be a Linux user 
- You asked what we all use?
So, I use Windows 7 on an old Thinkpad laptop. The reason I do this is because I use a lot of very standard office documents and workflows, such as Word 2010 and Excel, PowerPoint. I have drivers for everything and I'm very familiar with using it. Finding directions for anything I want to do doesn't take any amount of time at all. If I had more money, I would use a Mac. Because all of the above are also true of Macs - in fact, they're even more standard and easier to use, and very well-supported. I also at times do things like script parts of my workflow with hotkey scripts that have huge followers. The surest way that you can guarantee to just get an intsallation file (.exe) for whatever you're doing with no real steps in between is by being on Windows, which is used by the most people in the world who are using a Desktop PC or Laptop. At the moment for example I am designing a piece for 3D printing. (It's actually part of an Arduino project.) I needed a new CAD design tool. I've never used one in my life. The first recommendation I got that meets my needs is Freecad, and it's available on Linux, Mac, and Windows. But I didn't like it. Then I saw this video - which is provocatively titled "The Best Free CAD Program - DesignSpark Mechanical" (which is why I clicked it) and has 129k views, 1146 upvotes, noise floor downvotes. It starts saying :
Hey everyone, today I wanted to showcase one of THE best free CAD programs that I have EVER used. So I come from a background of using SolidWorks, and after using SolidWorks for years, I find that a lot of the free options just seem lacking. This is the first program that made me stop and go WOW, that is incredible. So this is DesignSpark Mechanical, and let me show you what it's all about. So you have the sketch laying here and I can sketch on it like you can with most programs, and I can draw this rectangle and just start typing in the dimensions. So I say I want this 40 millimeters by 20 millimeters -- it'll make that sketch and then I can then grab this sketch and pull it into a three dimensional...
and basically ten minutes into the video, you have this great understanding of this easy to use software. The thing is, in my research everyone told me to "just use SolidWorks", but it's not really affordable. As for DesignSpark mechanical: it's for Windows.
At the end of the day, anything you can do on Windows you can do on Linux. But, you may not have a particular piece of software. Whether it's Adobe Aftereffects, Autocad, Solidworks, Photoshop, or some other piece of software, you may end up working with an alternative. This is a great site for finding alternatives.
Finally, there is another aspect that may interest you. Ubuntu is derived from Debian, which has a very strong philosophy of "Free software", but here Free isn't about price, but rather a kind of public, common ownership that can't be taken away. That may be part of the why people don't try to run Photoshop under Linux (they certainly could try) but instead develop a Free alternative, in this case Gimp.
It is absolutely worth pointing out that Arduino is part of this open, Free software movement. Arduino is open source (which is a bit of a synonym for "free" - some people say F/OSS to denote either Free or Open Source. Normally this Free idea is even stronger, it means that the license means it must always be available and can't be closed back off into a commercial project.)
So if you want to be part of this open source movement where people develop software together, I would above-all recommend Linux for that reason alone. In my case I also use Linux, from within Windows, for example connecting to a Linux computer and also under emulation. However, the Linux I use isn't a graphical system (like installing Linux as mentioned above) but on the server side or small embedded boards.
I've written a lot but still didn't cover the reasons you'd use a mac, which someone else could talk about, since I don't use one.