Originally Posted by
Dev Jaykrishnan
the best implementation i've used is from the cyanogenmod team:
one press = back (wether it's a web page, setting, menu, text input block, whatever, it depends on the current UI's functions/processes)
double press = switch to previous application
long press = kill current app completely (good for a hung beta app), (and then a preset settting of the user's preference to...) back to app list, or desktop, or whatever was defined by the user
i can completely understand why users don't want to loose their back button. if this implementation was used, i can see real benefits in actually having one.