I too hoard high bitrate files so for me the big difference is that I won't turn down a 160 if I can't find anything higher, hehem ..
I have bad hearing, though, no way around it. In the studies, there are some that can pick the high quality files and these are people with good hearing who should arguably get their music in high BR. They seem to be a definite minority though. Satch, what you write is correct - one of the graphs I had in my post which is now sadly gone showed neatly how an mp3 up to 112 kbps could rather accurately represent sound of up to 15k hz or so before there was a rather steep dropoff point. 128k improved on this significantly, but would still create a dropoff within audible range for many if not most and the relationship between this dropoff and bitrate is not linear. An increase in BR does less for the quality the higher up you go meaning in theory there's a larger difference between 112 and 128 than there is between 256 and 272.