My game room only has one arcade machine and one pinball machine in it, but it's a hit at every party. Guys go home pestering their wives about building game rooms. Heck, even the wives go home talking about building game rooms. Why? Atmosphere.
I picked a theme and decorated to that theme. It was designed to be a space/alien type room. It has a funky, alien-ish color scheme (purple and green). There's curtains with planets on them, and the curtains completely block out the light from outside, making it feel like nighttime no matter when you're in there. A pillow on the couch is covered in the same fabric, pulling that into the theme. I also have purple LED lights running along the baseboard for kind of a runway (for aircraft not super models) feel. There's Space Invaders on one wall, Star Wars toys on a shelf above the arcade cabinet, and a Space Duel marquee in a lightbox on another wall. Even the air conditioning duct covers and the light fixture (always set on dim) are decorated with space stuff. There's still some things that need to be pulled into the theme, particularly the couch and chair, but I'm working on that too.
Having a Nintendo Wii and a metal DDR pad in there doesn't hurt either, but you could say it delves into the "more toys and games" category. However, what they bring to the table is something that arcade and pinball machines can't bring - they let the non-gamers get in on the action. The fact is, you're always going to have someone at the party that isn't into video games and never was a big fan of pinball. A surprising number of them will be willing to try out the Wii or DDR, though. I'm not sure if it's the physical activity that they like, or if it's the relative accessibility of those games, but it works.