I use Linux as a desktop OS out of choice. Originally, no - because I couldn't afford a MacBook, but I've learned to love it and I don't have any need to switch.

Linux desktop is an OS for people who are willing to invest time to get an utterly fantastic, fascinating experience. It doesn't suit modern instant-gratification culture, no, and yes, it takes experience and expertise to get the most out of it, but once you get there, it's bloody amazing.

I'd recommend having it as a small hobby as well as tool, so you can spend time learning and figuring things out and broadening your knowledge.

Disclaimer: Using Arch Linux with the i3 window manager. No, it's not for everyone, but I absolutely love it.

By choice here and have been using it for about 6 years now on the desktop and I have no plans of migrating anywhere else.

I have a Linux desktop at work and one at home. I actually see the modern Linux desktop as absolutely amazing compared to where it was a decade ago.

I also have a Mountain Lion MBP, but AFAICT, I will be leaving the Apple cart after it dies and I'll be 100% Linux.

Do you really think there are no people that use Linux by choice?

Choice here too - have been running Linux at home for almost 10 years and I never regretted it. There are almost no downsides, except careful choosing what hardware to buy and the lack of Photoshop (though Wine helps with that now).

I use Windows out of necessity at home to play my video games. I use Linux as choice as my IDE at work.

Both.

I need it for work, and I wouldn't have it any other way.

actually both. home and work. my children's friends think I am a hacker since my console looks like a hacker's computer.