This is an Apple Power Mac G4 Cube, from 2000, but beneath the beautiful exterior there's a monster of a computer. Instead of the original 450MHz G4 CPU with 256MB of RAM, there's a dual 1.6GHz G4 board, with 1.5GB of RAM, and the primary boot drive is an Intel SSD connected via Firewire. Not as fast as the newer Intel Macs, but more than enough for serious Photoshopping. It's beautiful.
Strobist info: ST-E2 triggering, on manual, a 580EXII from the top, @105mm, a 430EX hidden in the back, right against the computer's case (which lights up the acrylic), and and second 430EX behind an umbrella from the front/left at a very low power setting to add just a little light to the front.