Well, I've always known my aunt. She is technically childless though. She was unable to have children for medical reasons, and also wasn't allowed to adopt for the same reason. But, she's always been an inspiration to me. She has lived a crazy, fun, super fulfilled life: career, she still does her art, has traveled all over the world, has a loving husband, tons of friends, and a more active social life than me! If I'm half the woman she is by the time I'm her age (70), I'll be doing just fine.
My first boss when I was straight out of undergrad was adamant about being childfree (Biologists, I swear there is a significant [p-value < 0.05] amount of us compared with the rest of the world who are opting not to have kids). So, yeah, in my career, I've definitely met a few. Never men though; it's always the women. Strange.