A house. With a super LAN room. It would be really long and narrow, so you could have built-in desks along each long wall.
The desks would have rounded edges so you don't cut your arms while leaning too much on sharp edges.
The desks would have foot rests underneath.
The walls would have holders for cables and tons of powerpoints. The floor would be concrete (easy to clean).
There would be two wire bins at the end of the room, one for cans, one for McDonald's wrappers.
There would be wire holders underneath for the computers, so they can have adequate airflow.
There would be awesome ergonomic chairs.
There would be good airconditioning so that nothing overheats.
There would be great monitors, and computers able to handle the graphic needs of any game at highest resolution.
There would be great mice, those $200+ ones with the adjustable weights.
There would be 6 or more computers, monitors and mice because then my friends need not transport their computers to my home.
And there would be a kick-arse sound system. For amosphere
