Most people here spend most of their time inside a browser / shell / IDE / word processor, does the surrounding OS really matter that much?
Nope, not at all.
Doesn't stop hordes of people deriving their identity from a product though.
I agree with this. For the masses who are just running a text editor and browsing
www.ashemaletube.com you can use any OS really. Windows is pretty kick ass for gaming and it's hard to beat for that, for now. I haven't used Mac much, but it has a nice feel, and I showed my wife how to ssh into her Mac at work so she didn't have to drive downtown to get a word doc. Whatever product works best for that person, is the best product. Linux for me is the King, it started off as a passion and I turned it into a career.
Linux has its drawbacks like anything else. When compared to FreeBSD, Linux reveals itself to be a chaotic mess of glued together packages and a kernel that magically work together. The Linux communities can be goldmines of information or circlejerk threads of desktop customatization and Arch/Gentoo elitism. The Ubuntu forums teeter somewhere between 'Windows Vista Forums' and 'chmod 777 is the answer to everything' .
If you are a tinkerer, hobbyist or hacker (hate this word) then Unix like systems offer a true gem for exploration and learning. It's probably not worth the effort to switch if you are already productive on your current OS and don't feel like learning Linux equivalents like vim (which is hard as fuck to master). If you are sick of the bloat and instability that comes with Windows, then give Linux a try. The learning curve can suck at times but I can find no reason that I would ever need Windows again as my main OS.
List of suggetions for those interested:
Debian with GNOME Desktop
Linux Mint with GNOME or Mate/Cinnamon or w/e it's called
For those who want to learn how it works but not shoot yourself
Arch
For those who like coning
Gentoo
Slackware