^^^
I suppose I'm kind of in the same boat. I'm my dad's only son, and he was my grandfather's only son (well, only son that has the same last name as him, but that's a whole other story). One of my grandfather's brothers might have had a son or two, I'm not completely sure, but it would seem I'm also in the position of being the only one in my immediate family to "carry on the name" or whatever (unless my sister decides to give any of her potential children our last name... however, she's not overly fond of the name, so that seems unlikely).
I'm probably not going to have children, so the name might die with me -- and even if I had children, they might very well have their mother's name. Can't say as I care too much either way; it's not like there's any great history behind our name. Heck, it isn't even really our name, per se: it was the name of my great-grandfather's step-father, which he and his brother took when my widowed great-great-grandmother remarried.