regarding the decoration: i wouldn't put anything else in there if i were you, imho some nice lighting and a cool floor (perhaps some toppers 
) are good enough. i never understood the need to put marquees, beer signs or license plates on the walls. LESS IS MORE!!! 
So you don't like our gameroom at all?? With the marquees covering the light ropes? The huge TRON display? The Space Invaders-stickers on the wall? The small LED-Atari-Sign?
Hey, I didn't say "Cover all the walls with posters and marquees"
A poster here and there, maybe a nice (arcade related) neon sign and some coloured lights in the corners (maybe on the floor, lighting towards the ceiling) will do the job.
I have collected some arcade posters (large bitmap files) if you need any
