Thanks to everyone for this informative and, frankly, somewhat reassuring thread.
Last summer, on a flight back to CA from Prague, I sat in front of a family with a continuously shrieking infant. The child must have been sick; a week after getting home, my wife and I came down with severe fevers and, in my case, an ear ache. Long story short: I suddenly lost almost all the hearing in my left ear.
My GP sent me to an ENT who "diagnosed" the condition as "sudden idiopathic hearing loss" (more a description than a diagnosis, in my opinion). Apparently, this strikes about 1 in 10,000 people annually, and--as "idiopathic" indicates--it has no known cause nor any known reliable treatment. There's high-dose steroids (e.g., prednisone) injected directly into the ear canal (no thanks!), and the experimental "hyperbaric oxygen" (risk, besides cost: bursting into flames; again, no thanks!), but otherwise, I was told not to expect any improvement.
However, my own impression was that there was congestion in my Eustachian tubes; sometimes, swallowing hard would partially clear the problem temporarily. Besides, I'd just had a severe congestive illness. Sorry, the ENT said; a hearing test through the bone showed the same results as through the ear canal, indicating cochlear nerve damage.
I'm happy to say that he was mostly wrong. After some months, the ear began to clear more frequently, and now, it's almost--not quite--back to normal. I don't think I'm deceiving myself because, when this was in crisis, I was adjusting the balance on my audio system far to the left to compensate; now, the balance is set almost back at center.
As for tinnitus, yes, there's some of that, too. I think most of us past 60 have some problem with tinnitus. It varies in intensity, as several here have noted, and one gets used to it.
What interests me primarily about all this, though, is something few have remarked on and that may in fact be sort of taboo among audiophiles: the importance of subjectivity in the experience of audio bliss. After all, if you want to convince someone else of the superiority of your system, or of this or that component or tweak, you have to appeal to "objective" facts. Your friend can't have a pain in your tooth, nor can he have your experience that grounds your enthusiasm (he...or she--but face it, the vast majority of us are hes, another subjective factor surely).
Age related hearing loss should wake us all up to this fundamental feature of human experience. We may want to validate our enthusiasms as objectively justified, but they rarely are. Objectively, few of us can hear, coming from our many thousands of dollars of audio equipment, what our children can hear from their iPods playing MP3s through earbuds.
I know this is depressing, and kind of heretical. But...