Okay, I joke, I know several people who run linux on their desktop.
It seems like something that you grow out of, though. I use a mac, and most of the people I know who /really/ know [1]linux do too. In fact, the person I know who "knows linux" the most inside and out runs an ancient PPC macbook. I think he said he installed Ubuntu on his machine at work, though.
The reason for this is that we all run linux* on our servers. My primary machine is a VPS from linode which runs gentoo linux, and has for a very long time. The aforementioned PPC macbook guy doesn't really have a primary machine anymore. He is getting into power electronics, and is more likely to be sitting at an oscilloscope than a laptop.
Lately, my hobby box has been a raspberry pi which I'm looking to make it into a telepresence robot for our lab. Interestingly, live streaming video from a linux machine doesn't quite seem like a "solved" problem yet. It's lots of twiddling ffmpeg to make things work; things still aren't "plug and play".
This is cool, by the way, it feels like the first time I stayed up all night installing gentoo.
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I guess that for my peer group, linux was something that felt really revolutionary and new and important 10 years ago. We were battling against the big bad microsoft, THIS was going to be the year of the linux desktop! (No, MOM! You have to install Suse! It's totally easy let me show you!).
Then...we won.
Linux is just a tool for me. Like a hammer. When I want to use it, I pick it up and use it. It doesn't feel revolutionary and important anymore because it just feels /obvious/.
[1]: It's a bit silly to say "linux". I'm generally not specifically using any of the features of the linux kernel. Most of what I'm doing could easily be replicated on a *BSD system. Although this whole "gnu plus linux" debate thing is a bit silly. When I say "linux" people know what I mean. Sorry, Stallman :(