For me here's the problem: when I let people listen to my Senn PX360s or HD650s they arent listening to anything else at the moment. So they put on my headphones and acknowledge them as being nice and that's it. The only time I get a good reaction is when the person is wearing some other headphone (Bose, iPod buds, Beats, etc), they listen to my set, then immediately listen to the same song with their set and can hear the difference. Then and usually only then do they get the "WOW' response. I know that if you listen to something else, then put on nice cans it makes you appreciate your set more: I have a nice set of tower speakers (Wharfedale Evo2-30s), but after having a good session with my HD650s, the Wharfedales just don't sound nearly as good anymore, it takes a few hours before my mind forgets the sound of the HD650s and I can enjoy my towers again!
Only one time have I had someone listen to the 650s cold and say: "If I had $500 to spend on headphones, those would be worth it!" (and he was listening to an SACD being played through my very descent Yamaha S2500 via analog out). The PX360s usually have the bigger impact because those are my portable sets so when I switch with people, they are usually listening to their own headphones, so the impact is immediate. Also the price (~$120) and somewhat bassier sound (for a Sennheiser) makes them seem very worth it. I dont know many non-audiophiles that could justify spending $450-$500 (or even $370 which is what I paid for the HD650s) for a pair of cans, so the reception is less enthusiastic than with the PX360s.