Privacy and programming communities. I tried to stay at Windows at first, but when I was bith recommended GNU/Linux for privacy and had to use it for programming, I knew I couldn't keep the resistance up.
Three years later and I have 0 regrets. All games I play work, except for, recently, TF2 because of a weird malloc library issue on Arch-based systems. All apps I need just work, and whenever I need something Windows-only I have a VM setup just for that. Developing and managing your system on a Unix-like system is just so much easier.