Why 1280x768 rather than 720p? Is it for the software buttons? Otherwise it'd be odd to scale a pretty standard size for videos etc. or have black bars on the side.
720p screens often aren't 1280x720 anyway. Lots of HDTVs and laptops have screens that are labeled 720p and have actual resolutions of 1280x768 or 1366x768.
That seems wrong. If a phone is held vertically, the 768 pixels is the width, not the height -- so the buttons take a chunk out of the 1280, not the 768.
Sure, but I don't think anyone is worried about maintaining a perfect 9:16 ratio for reading text or what have you. Generally when a device like that starts playing 16:9 content it forces a switch to landscape mode with the content centered and at the top, leaving a 1280x48 swath on the bottom for the home bar and the top 1280x720 for native-resolution 720p content.
