One of My senses.

If I could keep one of my senses it'd probably be tasting. I love food and drinks and it would suck if I couldn't taste what I was eating. I probably wouldn't eat if I couldn't taste it.
Sight would probably be in second place because I could learn sign language easily and it would just be crappy to be blind. I love looking at beautiful things and people. I would definitely be missing out on life if I couldn't see the world.