Note: This post is entirely conceptual / brainstorming.

Like I said, when you're by yourself it's perfectly fine, but how about in a car full of screaming kids, or relatives?

I think body language can convey almost as much information as voice. If things get too loud, you just wave the volume down. You can take one finger pointed and a movement across the neck like a knife will shut the music down. Take a look at sign language, and the multitudes of information that it can convey, a tiny subset of that can easily be used for appliance control in the future. If you think minute motions of a single hand can't possibly convey that much information, think of what you can do with a computer these days by moving a mouse around. A decade or two prior, nobody would have thought it possible to do without a keyboard for computer control.

I'm not against voice recognition. If it's a choice between fumbling with a remote and voice recognition, then voice recognition might be something to try.

Does anyone here read Peter Hamilton's novels? Now Hamilton has a intriguing user interface called a datavise, a small implant where you can relay your thoughts into just about any appliance. Musical devices relay music directly back into the brain.