I think a "wow" is in order with the Scope Dog R/C mech. Plucked from the 80's anime series VOTOMS this 1/24 scale Scope Dog Turbo Custom can do it all.
Using the controller you can make the robot "roller dash" and fire its assault rifle. If you have two, you and a buddy can wage war by firing infrared shots from the guns. The controller will respond with sounds and vibration when your mech is hit. However, building up an army of these mechs isn't going to come cheap. Each one will set you back $US248. [Japan Trend Shop via 7Gadgets via DVICE]