Something people forget about, I bought a 5 pack of Plantronic headphones that were noise canceling (with a mic) and were surround sound for $20 a pair, but with the 5 pack you are paying $15 for them.
They have been pretty awesome without any issues, either got them off Amazon or Ebay. Basically it comes with two speakers per ear - a front/back setup which offers limited surround sound, but in Aces High it has worked out quite well.
I mainly use Twinbooms soundpack mixed with a few odds and ends, the new storch for example simply sounds awesome.