Forgive me if this has already been said somewhere, but it just occurred to me that the features I'd MOST want to toggle with the iPhone 3GS Voice Control are the ones which are buried menus deep. Imagine, instead of clicking Settings > Bluetooth > On/Off, just holding down the home button for a second, then speaking "Bluetooth, on/off!"
Same with "Wi-fi, on/off."
Or "Airplane mode on/off."
Seems like this would be an easy thing to do in a .1 software update.
Just thinking out loud.
And again, if this hasn't already been discussed, feel free to submit it to Apple. Take credit for it, too, if you want.