One of the key things I've been looking for in hand-held devices designed (in part) for reading is a screen resolution of at least 300dpi. I have questioned that in the past, but it has always been a goal. I hate reading on computer screens and I've always felt a higher resolution would help.

The new iPhone has a resolution of 326dpi. Tim Bray questions if such a high resolution is necessary, leans towards yes, but worries about the cost (in hardware/software terms, not $).

I'm firmly on the yes side, particularly for a device as small as the iPhone. If you're going to have a screen that small, you need a higher resolution to make the text more readable.

I have no science to back that up...