it may not be good idea for deaf to own iPhone during the lack keyboard to typing during the touch-screen only. It's more slow to typing. I have experienc with original PDA without QWERTY available and had to "write" into character by time and time as fast I could.
And it wouldn't be much entertrainment since there is no CC or subtitle available when purchase to download movie/tv show. And there seem have no video mode under camera as camcord. That kind something dissappointment. It would be neat if there is a way to install Photoshop on iphone since it's running by Mac OS X. But the size memory may be problem to suffer.