I’m a traditionalist at heart, I prefer my gaming done around a table, with minimal distractions and with easy access to all the required gaming materials and refreshments.
I prefer the table because I find it focusses players on the game much more than being sat around on sofas or the floor. While gaming should be pleasant and relaxing it generally means that the DM has put a whole load of work in and sitting around a table helps players commit to the game more since it’s a reminder of why they are present where as being sat on sofa’s can give the impression that it’s any other social gathering.
The rest kind of depends on the game. For horror I prefer the room to be dark and candlelit, otherwise I prefer the light focussed on either me or the board if we are using one. Atmospheric music in the background is a bonus, if the right piece can be found. I prefer phones turned off, although tablets are acceptable if it fits for the game, and these are becoming increasingly more common. The room should be cool, but not cold, though this is way harder to regulate and my own game room gets uncomfortably hot.
My own game room fits many of my criteria but it’s not what I’d call perfect. Perfect to me would be a large, dark wood panelled room. There would be a large, marble, central table with an inbuilt touch screen for generating maps etc. Each player would have their own in built screen linked to the map for purposes of annotating it and they’d have access to PDF versions of their character sheet and relevant rule books. The DM would have a central hub computer with access to all the player screen plus the ability to manipulate and central screen to display new sections of the dungeon, add monster etc.
Each player would then have a set of shelves behind them with copies of all the relevant books they might need in physical media, should they prefer that. The room would be temperature controlled, noise proof and have tea/coffee making facilities plus storage for snacks and a fridge. The DM’s control panel would be able to control the lighting in the room and would have wireless access to a media library of music and sound effects and would be able to play them through the rooms inbuilt speaker system.
Finally, the whole room would be hidden behind a secret door accessed by pulling the correct book from a bookshelf in the study of my house. That would be my perfect room, one I’ve been planning for a great many years and is pretty unlikely to happen, but that’s the dream. Maybe if I win the lottery….