This Interesting thread is of professional interest to me as I work in professional Audio.
Sennheiser are well regarded in the business for their audio equipment. Their headphones are personal favorites of mine and also for a lot of the people I work with. I agree headphones for professional use are quite expensive (£140 on up), but the sound quality and wearer comfort tend to be far superior when compared to cheaper gear. Anyway here is the link to Sennhieser aviation headsets page.
www.sennheiser.com 