I'm looking into getting some nice headphones. I've narrowed it down between Sennheiser HD485 and Sennheiser HD555. Both fit my price range, but with some research, I found out that both are open headphones, whereas I originally thought HD485 was not. One question that bugs me about open headphones is how much ambient noise they produce. Is it enough to disturb people around you? How bad is the problem of ambient noise coming into the headphones? Also, if anyone has an opinion on which of the two headphones above is better, please tell. Or a suggestion for another pair preferably less than $100.