I am hypersensitive to sound but take the onus upon myself to deal with it. Certain harmonics, repetitive sounds, or sounds that vary in modulation are enough to put me over the edge. Can't take whistling or humming, either. It actually stems from when I was severely hypoglycemic-noise intolerance is a symptom. So I find my own white noise, use ear plugs, or just do my best to ignore. It is VERY tough sometimes but I recognize I am the one with the problem.
I can totally relate to Crowe here, though I don't have a medical reason for being sensitive to noise. And like Crowe, we came up with a solution which blocks most noise (deep bass, though, still booms through). Actually, I think I wouldn't mind the neighbors' a/c running (as long as it sounded normal and wasn't clanging or something); that could be very soothing. Siding with everyone here on this issue.