Watching a movie on the new iPad will not as pleasurable experience as you might think. The screen being 1024x768 pixels is in a 4:3 ratio which is the exactly the same as an old CRT television set. Many of us are have gone on from there and are luxuriating in the glory of our 16x9 aspect HDTVs.
It turns out that 16x9 will give you big honking black bars at the top and bottom of your screen as you can see by the green bar in the image above, and anything above or below it will be displayed as black bars.
It gets worse, lots worse. Let's say you're playing a regular, non-widescreen movie which has an aspect ratio of 1.85:1. In that case anything above or below the blue area will be black bars.
Now we get to ribbon-vision. Most widescreen films, from Star Wars to the new Star Trek were filmed in 2:35:1. This and all other resolutions mentioned refer to how wide the screen is as compared to how high. So these films are 2:35 times wider than they are high, and result in a mere ribbon on the iPad screen. Without measuring, it seems to me that a full half of the screen in landscape mode will be filled with black bars.
One last kick in the pants. Having a resolution of 1024x768 pixels there is no way that you can display the gold standard of today's high-definition of 1080p. There just aren't enough pixels.
So iBooks make sense, but movie watching will be somewhat limited. People frequently say that they really can't watch movies on an iPhone or iPod touch, since the resulting display is so small. The iPad will absolutely be better, but still at a trade-off.
Thanks to Blake Walters for creating the chart and tipping us off about this.
Note: Some users have questioned the graphic, so I'm posting a revised version by Arash Ayrom which is correct.
Here is Arash's graphic: