This came up last night in a conversation with some friends, and everyone agreed that they'd rather be deaf than blind. I would prefer to be blind though - I'm not super visual, and I just love to hear the sound of my kids' voices. Imagine not ever hearing them say "I love you" ever again!
Being blind would probably hurt my career more than the alternative, since I rely on reading and writing in my work. I still think I'd choose to be blind though... just so I could still talk to my family and friends.
If you had to choose, would you rather be blind or deaf?