How important is a flat response?

I would like to hear Rives Audio's input on this one!
Rives?...
Also, I know a little about at least seeing pictures of what room modes look like, and I have a question. if you use an equalizer to eliminate a frequency mode, does that remove the dip at that frequency? If so can't you simply remove all the bass modes with an equalizer, dips, peaks and all? I'd like an asnwer to this. Or, can you simply eliminate the peaks in a room with an equalizer, like the Rives PARC. Maybe I should email Rives myself.
Rives?...