I always use mine in landscape but partly because my case is awkward when it's in portrait. But also I think it's just better in landscape 90% of the time.
The iPad buttons seem to have been designed mostly for portrait use though which is odd. But most people seem to use theirs in landscape, and most cases are meant for mostly landscape use. Also most TVs and monitors are wider than they are tall so it just feels more natural. The formatting of most websites just doesn't work in portrait.
I also read magazines and books in landscape. It just feels more natural. I think it's also more comfortable and easier to hold, but then again I do have large-ish hands to fit my lanky 6'2" frame.
Hasty said:
Since my eyes are on the level I tend to go with horizontal.
Of course if they were vertical I would probably incline the other way....
Hahah very true, this may indeed be why portrait feels much more natural to me! Also as someone else said it does usually mean the text can be larger whilst still fitting everything on the screen.
Why is it tough that many people use their iPads in landscape with the home button on the right? I find it odd having the side buttons closest to me where they just seem likely to get knocked. But with the home button on the right, it does feel as though the volume control is the wrong way round - left is high and right is low, so I still keep turning it up instead of down & vice-versa.
iPad Buttons is generally landscape or Portrait. If you are playing video game or View a video, You want to Landscape button. The ipad Buttons is using more and more and smooth.
I find the orientation of My iPad to mostly be in portrait mode. I find the home screen to be (I don't know how else to put this) more pleasing to the eye in portrait form. :ipad-front: