Linux has fought its way up, and is now the defacto standard operating system. If you intend to continue your career as a software developer, learning Linux is absolutely essential.
If you are not a developer, but haven't tried Linux yet, you really need to try it. Just download Ubuntu, It's free. "Tech support" is community driven so when you post a message on their online message board asking for help, you will get a reply from a real person who once had the same problem as you. You can also buy more proactive support.
You own the Data You Create
The most important reason to use Linux is that your data belongs to you. When you change from Windows to Linux, you may loose some of the data you created because you will no longer be able to use the software that created that data -- that software only exists on Windows. What happens when you want to use a computer made by a competitor of Microsoft? You will never see that data ever again, Microsoft won't help you move to a competing platform. This is explicitly Microsoft's strategy: if their customers find it too difficult or too costly to use anything but Microsoft software, then they don't have to compete with other software companies. For the longest time, Microsoft simply never had to compete in the desktop computer world, and this is why they have consistently failed to innovate.
This is not true going the other way. Take for example Ubuntu and Android, which are both based on Linux. You can switch back and forth between them without losing your data, because software written for Android can (and usually is) made to work on Ubuntu, and vice-versa. This gives you, as a consumer, much more freedom and choice. Any operating system based on Linux will have this freedom.
There are laws governing the Linux world, colloquially referred to as "open source" software. This law essentially requires that of anyone who writes software that they must always provide the option of making the software run on a different platform. This means, even if the original author of your favorite software is unwilling to make it work on that new computer you bought, fret not for as long as software is useful, you will be able to find at least one person smart enough to keep that software running on Linux, and the law guarantees that this person will have that freedom to do so. It is like a lifetime guarantee on the data you created. The software you made it with will always be around for any operating system, so long as there is interest in it.
This quality is paradoxically provided to you by the the General Public License (the open source law governing Linux) which explicitly states that there is no guarantee of any kind associated with the software. Linux, and most all Linux software, always have attached to it the following legal disclaimer:
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.Practically speaking, what this means is that programmers have the freedom to make the software work on you computer without worrying about being sued. It is this freedom that allows for innovation.
Linux is the Operating System, for Any Computer
Linux is the most used OS in the world, and is used almost everywhere, excepting only home desktop computers and laptops where Windows obviously still has a death grip -- and now even that is starting to change. It hasn't happened yet, but there is very real potential for, Android, Chrome OS, or Ubuntu to start making their way as a true competitor in the laptop and desktop world. Apple seems less interested in home computers these days (more interested in cell phones and tablets), and that leaves lots of room for Linux in the home.
In fact, Linux is already in the home on TiVos, making your TV set work, and it is the heart of the Android operating system so it may well be in your cell phone too. Linux runs the Google search engine, Linux runs Facebook, Linux runs the majority of all applications on the internet. Linux is just not the operating system on your desktop PC.
The Lost Decade of the PC
The desktop computer platform has been hurt the most by the innovation vacuum caused by Microsoft. People still think either Windows with MS-Office, or Mac with MS-Office are their only two choices. Many people still think software comes in discreet units that you can buy in boxes off of shelves at Wal-Mart and Best Buy. With this old way of thinking, you may have found yourself in this situation:
Yay! The computer I bought from Amazon.com has arrived on my doorstep today... but I need anti-virus software. I'll guess I'll just pick one up next time I am at the mall.
Now, Windows is starting to fade away, and the iPhone and Android "app stores" have taught people just how ridiculous this old view of software is. Microsoft is fully to blame for making you think things would have always been that way. Now we know better: you don't buy software in boxes. This is how the world works now.
And incidentally, if people are going to pay for an operating system, then anti-virus should be the responsibility of the software maker, not the consumer. The Warranty on Microsoft Windows disavows any responsibility to any loss of data caused by viruses. The difference between Windows and Linux is, therefore, that you pay money for Windows, but if you ever get sick of dealing with Microsoft, you aren't allowed to change to a competing operating system without losing much of your data. Sure, Linux doesn't guarantee protection from viruses either, but at least you can move your data from backups onto another operating system if you want.
Things have evolved, but Microsoft has not. In fact, Microsoft has just signed a new agreement with all of their OEM's to make it impossible to install Linux onto their computers unless you disable the "Secure Boot" security features which they are now bullying the OEM's into installing into their hardware. Microsoft shows no sign of wanting to actually try and compete with Linux by innovating.
The simple fact is, they cannot compete; Microsoft does not have what it takes to survive in the software industry anymore. They are merely coasting on the momentum of general consumer ignorance, the popularity of their Windows, Office, and XBox, product lines, and by taking advantage of the patent and copyright laws that protect them from the competition.
The Bright Side
Personally, I am most thankful that Steve Ballmer has done such a terrible job, he has effectively weakened Microsoft's death grip on the software industry. As a result, we are seeing a small explosion of innovation, particularly with the idea of cloud applications and app stores. Nowadays your average Joe knows there is more choice than just "Mac or PC", now you have Android and Ubuntu in the game as well (although Ubuntu is still most unfortunately _not_ a household name).
If software patent laws weren't so thoroughly hindering innovation in software, we could see what the computer industry mature to its full potential, we could see what computers are truly capable of. But we are fortunate to have a fleeting glimpse of that full potential now that Microsoft is much less the monster it used to be. The software world we see today would have happened much sooner had people not been convinced that Microsoft was the only operating system worth using all throughout the 90's and the first half of the last decade.
To be honest I hope this new Apple CEO, Tim Cook, is to Steve Jobs what Ballmer is to Bill Gates. If Apple goes down, and Microsoft stays down, and if software patents are decided to be illegal, then you won't believe how much competition and innovation we will start to see. I think it is completely possible that the resulting technology could improve the quality of life for every person on the planet, if only it had that chance.