In Sherrilyn Kenyon's Dark Hunter novels, there are quite a few Buffy references. She's said before that she was a huge fan of the show, so I'm assuming that she gives it a nod here and there. Also, when I went to JemCon last year, Christy Marx, who was the head writer for Jem (and she also wrote for He-Man, Transformers, GI Joe and numerous video games) mentioned Spike in her Q&A session. It just put a big smile on my face that someone, who I see as an icon, also loves Buffy and the characters from the show!
Oh, and I believe it was 3 or 4 years ago, we did Halloween in downtown Nashville. We went to this club where they had Goth night on Sundays and Halloween was on Sunday. Anyway, as I got off the elevator to go to the second floor, these two people who were dressed as Buffy and Spike were making out in the hallway. Just thought that was kinda cool, not that I'm a perv or anything, cuz I'm so not.