HTC Desire Z's slide mechanism, in my opinion, is a true gadget design wonder.
The screen doesn't just slide up to reveal the keyboard; It lifts up and snaps in place.
And because photos just aren't enough to show how great that hinge is, I've taken the liberty of shooting this video to show you how it works. Check it out --
I also tried to show the construction and other design elements of the phone just to give you an idea of how well the hinge integrates with the unit design.
You know why it's like that? The screen lying almost flat with the keyboard means not only a more streamlined look but also less thumb-banging with the rim of the screen when you start typing on the keyboard.
Much thought has been put into designing that hinge, you can tell.