I'd go for Hearing (Same trend), mearly on the fact that without sight i don't know whats going on, even though i would hear it, smell it and maybe touch it (not too sure about the last one, when it comes to a motorway...) Anyway loosing my Hearing would also stop me from speaking(after a while), but i could still write. But loosing my sight would allow me to still talk but not write, or see what i am hearing. Losing sight, as said by xenex, would make me lose perspective on the world, but losing my hearing would keep and preserve the pespective side of things. But people have diffenrt ways of dealing with these incedents. (mine would be a tight rope around the neck and a 100ft drop...as i could not bear the thought of loosing and of my senses.)