Well, thanks everyone, for your kind words. I guess at this point I'll put it down as a 0 cm AN, subject to revision.
My audiologist, without actually saying so much, seems pretty assured that this is what the problem is. He said any one of my current symptoms alone would necessitate a visit to the ENT for an MRI, all of them together, well, it's imperative. I think what caught him most was the dramatic change in my audiogram since October 2005. There's a substantial drop all across the spectrum, with the largest in the high frequency range. And all this with the left ear humming away perfectly. No, uh, sorry, it's the right ear that hums. The left ear is pretty well behaved, just sitting there listening. The really strange thing was the bone conduction test. Every time she put a tone into my right ear, I heard it on my left side. And I must admit, I felt kinda funny sitting there when the test was going to start in the right ear, and I'm thinking "Ok, well, let's get it started." Apparently she had started it, I just didn't realize it.
I must admit it's somewhat concerning me right now. I felt suspicious that I had one back in 2005 but was relieved when I didn't. I don't want to say that I know it's there, because I don't want to come across with doom and gloom. It's just that there's something pretty wrong going on in my right ear, and it's getting considerably worse with time. I'm wondering what else it could be? I guess the most important thing is that I really would like an answer to "what's going on"? Maybe it's that M&M that I put in my ear to see if it would melt. Or it could be that microwave that I repaired myself. I thought all of these safety gadgets were stupid. Guess it would be ok if I hadn't kept watching the food cook? Or maybe I shouldn't have boosted my cell phone to 300 Watts.
Well, time will tell. The hardest part is the waiting. I'd rather just hear one way or another, good or bad, so I know and then can deal with it.