I hear you about the loose lug nuts. I once did have all five on one wheel
a little loose. I started to sense it as a vague shimmy accompanied by a
growling noise. I first thought "bearing", until the effect progressed to a
more definite wobble. Glad I figured that one out when I did.

As for the wheel bearing: I'm the originator of this thread. I had the
bearing on the right rear of the car recently replaced by a mechanic I
found in the cartalk.com mechanic finder. I was impressed by the mechanic
and the shop. The price was in line with what I'd come to expect: ~$325.
I'm very happy to say that the particular noise I associated with "bearing"
is gone.

Thanks, everyone, for your helpful suggestions and your support!