how many watts, a 2.1 speaker typically consumes??

very little & that too when playing some sound.usual PC speakers don't require any power as they just play sound sent from the sub/woofer which has the amplifier.that is why the power chord in 2.1 speaker system is connected to woofer.usually RMS value in watts gives an idea about power consumption.e.g.a typical cheap 2.1 speaker system like Logitech Z323 has 30w rms & assuming an efficiency of 60% that means when playing a sound at full volume on this speaker system power consumption will be ~50w(60% of X=30 so X=50).