Airbus have designed an excellent system with a latch-on switch on the radio panel, and a spring loaded switch on the stick. At my airline the infinitively wise management have decided that we are not to use the intercom system. In addition to this decision, a statement in the FOM says that when the headset is used (anything except for cruise), the speaker will be in the off position. In essence, you're left with the choice of using both earpieces to hear ATC, or using one earpiece to hear your fellow aviatior. I guess accurate communication is not necessary for safety.