Well, I don't plan on having kids for a long time, but I do like a lot of the names they use in the shows. For guys, I'm going to go against the majority and say I don't like the name Xander that much. It might be because I know a guy named Xander who I'm not the biggest fan of, but really, I just think the name is too...plain, I guess? Aside from that, the main guy names I like are Angel and Wesley, but the only name I could actually see myself using is Wesley...I would never be mean enough to name my son Angel!
Like Lyri and Joyce said, girl names are so much easier! Joss came up with a lot of great girl names; I could definitely see myself naming a daughter Willow, Anya, Fred, Dawn, Tara, Inara, Darla, Kaylee, River, Gwen, or Lilah. I would never name my daughter Buffy, though; the character is way too popular for people not to get the reference. Besides, I just don't like the name.