I voted landscape, except for reading.
Posted from my iPad WiFi 64GB
Imagine if you didn't have the option? *shudders
Portrait for reading books, landscape for everything else.
Depends on the app and what I'm doing, but otherwise usually in portrait mode (mainly because of the leather folio my iPad sits in.)
I love using portrait when I don't have to do a lot of typing, It feels a little more natural for me. But I couldn't live w/o landscape!
Odd question really as I never think about it, just turn to get more on screen.
Graphically horizontal is more instinctive, as eyes are not vertical, but for the written word it's always portrait as it's the common page layout. Nature and nurture in harmony.....
I use landscape for browsing and most applications.
I'm using landscape almost always