Well I have both HD485 and HD595, I have'nt tried HD555, and my comparison for both are:
HD595 are more comfort ,cooler and stylish than HD485 and also the whole ears are inserted in HD595's aperture and broader than HD485 one. I can hear some sounds in HD595 which is not clearly appeared in HD485 (espacially in Mid-range) with wider soundstage than HD485 as well. however, some reviews complain about the low bass, for me it is balanced, you need to tune your bass setting (e.g. bass boost), so this problem is easy to tweak unless you tries better headphones (such as HD650 with very strong bass as
others stated), coming to HD485' bass it is little aggressive as other mentioned(like Techno preset), I think it is the storngest point in HD485 than HD595, else other people complain about the sound leakage, it is the nature of the open headphones if try to block the other sides you will hear
different sound and unpleasent to you so it is a must for HD595 to leak the sound inorder to perform the best and it is for home purpose entertainment not forv public places and for me I use them in my room and even I prefered them over creative Inspire 2.1 interms of sound detail. There are HD555 which are similar to HD595 and expected to have the same comfort at affordable price, I chose HD595 because I want to get the absolute sound.