just curious why the odd resolution? I know it's 16:9 and everything designed around 16:9 will be in the right ratio.
But why that resolution? Why not the standard 1280x720?
Because that would cause odd scaling of apps. With the same 640px width apps can just be letterboxed.
With a 720px width apps would either be scaled 1.125x in the horizontal, leaving a lot of blurry pixels, or they would be inset 40 pixels on each side.
Plus for new apps you would have to design for 2048x1536, 1024x768, 1280x720, 960x640 and 480x320. Which means you are still better off than an Android dev, but Apple users like their pixel perfect interfaces, whereas most android users don't care. (This coming from a developer, using apps on both devices it is easy to spot the differences when an app was not designed for a specific resolution on the Nexus 7.)