Neat decoration for a gaming room. eBay with bullseye_deals has the 1342-piece MEGA Showcase Microsoft Xbox 360 Collector Building Set on sale for $116 - 25% off in cart = $87 with free shipping. Includes a buildable Xbox 360 replica (3:4 scale), controller with working lights, and Halo 3 game box. For ages 18 and up. 

The only other thing that would be a perfect addition is a light-up "Red Ring of Death".