Swonk prefers OpenBSD. OpenBSD is a general purpose Unix operating system. It emphasizes security and correctness. OpenBSD runs on several different architectures.
Linux is the mainstream Unix like operating system. Swonk often uses Linux for specific software or hardware that is best supported by Linux. Generally Swonk prefers Debian or Ubuntu.
Swonk likes Apple computers, and on the modern Intel Macs Swonk runs OSX. For the most part it just works. It's easy and it's pretty.
Swonk is not a big Windows fan, but sometimes it is the path of least resistance.