the Sennheiser PC360 is one of the best headsets on the market. I wouldn't part with it.
plug the Sennheiser PC360 into the Pioneer SC-LX81 and see how it sounds. headphone support is usually a low priority on receivers so don't expect to be blown away.
odd because people really enjoy Battlefield 3 with the Essence STX mainly the Dolby Headphone support.