I hold the phone with my left hand, I am left handed, and the antennia is on the home button side. if I cover the antennia with my hand it slows down and I get 2-3 less bars. On the iPhone 2g edge it was more noticible Also this is the default way YouTube and many many aps open. Also when the phone is charging, the cord isn't in my way of holding it. I'm supprised you right handed folks hold it with the home button on the right. Also the speaker is not blocked by my fat hand.
I don't use my heaphones in landscape, always verticle.