In her new book, The Scent of Desire, Rachel Herz argues that if it weren't for the sense of smell, sex would barely be worth bothering with. Smell triggers emotions more strongly than any other sense and is deeply tied to memory and attraction. Which might explain why Napoleon famously wrote to Josephine, from several hundred miles outside Paris: "Home in three days. Don't wash." (We're guessing she didn't write back: "And please douse yourself in Axe Bodyspray.")

And even if a diminished sense of smell didn't stop us from doing it, we'd probably be a lot less successful in choosing the right mate: we are unconsciously attracted to people whose genes are most different from our own, and we sniff each other out to get the scoop. This was recently proven in an experiment that asked women to rank men's sexiness based on their sweaty tees.

But let's say you could choose: which sense would you miss most during sex? Assuming you could spend all day long with five senses but had to lose one sense while doing it, would you rather sacrifice sight, sound, smell, taste, or touch? (If you need inspiration, try renting the unbelievably crappy At First Sight starring Val Kilmer and Mira Sorvino for a syrupy lesson in how sensory deprivation can make you a better lover. On second thought, don't.)