My FIL had very poor hearing and tried out several digital magic-ear contraptions. Even though all the tests indicated that his hearing was much better with them than with his old, in-ear, analog aids, he hated them. He could hear too well with them and never could get used to the new ones.
Background noise is a big problem with hearing aids. Especially if your hearing has been bad for ages, suddenly being able to hear things that you could as a kid takes a lot of getting used to. If you're a cranky old man who's used to simply turning the TV up all the way and telling people to speak up, well, suddenly being able to hear street noise, and air conditioner groaning, and the refrigerator motor, etc., etc., is a big change.
I like your idea of multiple programs:
1) Idyllic pasture.
2) Opera.
3) Noisy Bar.
4) Mother in Law.
5) Telemarketer.
:-)
I assume those days are coming, but maybe you can help them along. If you believe the hype, everyone's going to be wedded to an iPod and/or cell phone soon, so we'll be used to carrying around noisemaking gizmos. Having a [link|http://www.dspguide.com/|DSP] plugin for it would seem to be a nice feature. You'll have to be quick though; I assume Bose, et al., are already working on such a thing.
Best of luck to you and Thane.
Cheers,
Scott.