I love aural porn. I first got turned onto it when we had a power outage in the apartment I lived in at the time. The neighbor across the hall got into it in her living room which was adjacent to the common hall. She was LOUD. Ever since then I have been a bit of a perv about it, including walking the halls of hotels I'm staying at listening for people having sex. As far as commercial porn goes by FAR the best is
http://www.ifeelmyself.com and it's sister sites
http://www.ishotmyself.com and
http://www.beautifulagony.com/. These sites are run by women and the content is VERY hot despite being about as different from most porn as you can get and still being sex.