Weirdly, I ponder this question a lot (though I choose between sight, hearing, and sense of smell lol).

So answering this is relatively easy because I have already thought about it!

I couldn't imagine being unable to see. There is too much beauty around, and I would miss sunsets, and clouds, and all of the quirkiness in the world.

Hearing seems like it might be easier to lose because you can use everything else to kind of make up for it. Except, you can't. I adore music and to be unable to hear it anymore would break my heart.

So, I would have to go with touch. Which is also a horrible thing to do as I am an extremely tactile person. But it seems like the lesser of the evils compared to losing sight and hearing.