My wife and I each have a 5D2. She asked me to investigate tethered shooting/control for landscapes and timelapse work. The idea being that a decent size screen would give a better opportunity to compose and focus accurately, particularly with our new tilt-shift lenses. Another possible benefit might be easy and accurate long exposures, without purchasing a separate remote control.
I've read both of those threads, thank you. I've got an HTC One X, so DSLR Controller looks like it could be promising, with minimal outlay.