I usually toggle between flat and boosted frequencies on a couple of pairs of speakers. Alot of listeners tend to boost/ megabass switch the stereos, so that always gives a perspective of how exaggerated it can get. I never mix (or master) something without having the exaggerated bass response, at least as an occasional reference. Headphones, the car stereo reference mix, etc....this all helps. It's sort of horrific at times taking it onto the car stereo, but like it or not, that's where the mixes will be listened to a good portion of the time by people.
