I love Sirius as a name on paper, but be an R/S shipper long enough and you'll get SO sick of the "Are you serious?" "Why, yes! I am!" pun that you'd never, ever consider naming a child that. :P (However, if we get a black dog, his name WILL be Padfoot.)

I actually vowed that we wouldn't use a HP name, and I literally SCREAMED when I hit the part where Snape's father is named Tobias, because that was the name we picked out for a boy. Fortunately, Tobias Snape is (at this point) a very minor character, so no one but the most ardent fan would catch the similarity, and even West Wing fans (where we DID steal the name from) don't frequently pick up on the Toby connection, so it's no big deal. But I was so mock-furious at JKR for that!