I remember one time using an Audio Control C-101 equalizer to EQ my system's room response so it measured flat. The Audio Control unit came with a microphone and automatic EQ software to enable this to be done.
The funny thing is the results absolutely sucked, and the Audio Control manual (which is perhaps the best manual I've ever read...helpful and humorous at the same time) said they'd probably suck.
I'd be very surprised if most listeners would really prefer flat room response given the opportunity to A/B the options.
Good hearing does not have a flat response.
http://www.engr.uky.edu/~donohue/audio/fsear.html