Obviously super-powered, can run anything at max settings idk whatever, not much to say.
Nice Fancy controllers. Custom made Gamecube controller. Razer Xbox One controller (I have the Razer 360 controller and I really like the 4 buttons on the back + two buttons on the front). Probably Scuf PS4 controller.
Would have a Wii, Wii U, Xbox One, and PS4 all nicely set up on very short shelves where you can only access the front of them. Xbox One and PS4 controllers sit nicely next to the Gamecube controller in special holders on the desk. Everything would be positioned so switching the GC controller from Wii to Wii U to PC would be very easy to do with just one hand.
The Wii would obviously be softmodded and would USB load Melee, play Brawl with Gecko OS (for textures), and PM via PM Homebrew launcher. Also it would have 64 on VC.
Three monitors (none of which are CRTs >_<). A 4k (let's make it 8k) monitor on the left that would be used for standard computer stuffs and videos and Netflix and Smash Ladder and the like. A super low lag monitor in the center that would be used for stuff like StartCraft, Counter Strike, and Dolphin. Another super low lag monitor on the right would be used for all the consoles. There would be a switch for which it displayed.
Obviously nice gaming mouse/mousepad/keyboard/headset/chair.