I know this might be a stupid question but,
I just got done watching babel (great movie) on hd dvd. However this time there were no black bars on the top and bottom of the screen, all the other hd-dvd's i've rented from netflix have black bars. I much rather prefer the full screen hd picture without the black bars as i'm sure we all do, so why do some movies have it and some dont?

And is there any option to remove them without distoring the picture?
btw i'm watching on the 360 hd dvd add on

Maybe Babel is presented in a 1.78:1 (16:9) ratio which would fill up your screen completely as it is 16:9.

Other movies are in the film ratio of 2.35:1 or 2.40:1 which, when displayed on a 1.78:1 screen, result in black bars.

Different movies have different aspect ratios. Babel is 1.85:1, so there aren't any bars. Casablanca is 4:3, so the bars are on the side. Something like The Matrix is 2.35:1, so you get bars on the top and bottom.

This has nothing really to do with "HD"... it's no different than with standard DVD.

http://www.avsforum.com/avs-vb/showthread.php?t=824239

Here's a sticky thread on aspect ratio's that should help explain your question

http://www.avsforum.com/avs-vb/showthread.php?t=824239

^