I'd have to go with sound. While pondering this question on various perambulations, I realized a preference for vision as beneficiary of the Sense of a Lifetime Award. The auditorium of sound all around us is vital and juvenating, absolutely, but if I couldn't see words, it would leave me a hollow shell. A wreck of a man. A useless twit in sunglasses. Words are life and I'd keep my eyes at the cost of my ears, if it ever came down to it. Some kind of Van Gogh syndrome, I suppose.
All of this thinking out loud is predicated on the loss of hearing, as opposed to being born without it. I'd retain my memory of the sound of music. I might even remember The Sound of Music, seen once as a wee sprout. It's a remote possibility, but not impossible. Working at an Alaska cannery years ago, it amazed me how many movies I recalled on long shifts of mind shattering tedium. We were as good as deaf in the roar and tumult of massive machines. Sometimes unbidden an entire movie would reel through my head, sharp and clear as if it were being projected on a screen. I still needed to see to perform repetitive tasks, simultaneously reviewing the large catalog of a dyed-in-the-cotton cinephile. It spared my mind from otherwise maddening ravages of the job.
I can hear morning gridlock outside as I type, rough ambience. Yes plays on the stereo. Doors open and shut throughout the house, boards creaking as people move from room to room. Blessed sensorium.