Spoiler alert: I am also the maintainer of Pop!_OS and the Principal Engineer at System76 so it will be easy to guess.

I have loads of computers (which helps when doing OS work!) but my main one is my desktop. I have a System76 Thelio Mira with AMD Ryzen 9 5950X CPU, AMD Radeon RX 6900 XT GPU, 128 GB DDR4-3200 ECC RAM, a couple PCIe Gen 4 drives, and a couple larger PCIe Gen 3 drives. The most important parts of my setup, though, are my System76 Launch keyboard and 3x LG 27GL850 monitors. There's also probably a mouse somewhere.

This computer runs primarily Pop!_OS 22.04 LTS, but on those extra drives I often have some other OS's installed for testing. I also use loads of VM's, as you can probably imagine.

For apps, I mostly use Alacritty for my terminal, Firefox for my browser, and Vim for my editor.