Love, Love, Love Darla. Moreso on Angel than on Buffy, but I did think she was an awesome character, who had one of the best developments on either show.
I loved seeing how much she changed, from that dying prostitute The Master sired, into a mother who gave up her life for her unborn son, and came back to try and help him. (yes, I know people think it was The First, but I will always believe it was Darla)
loved darla, even chose to dress up as her for halloween one year while my friend went as dru hehe
i loved her backstory and how she was the masters pet and then seeing her past with angelus, a lot of history, shes a wonderfully dark character who i was sad to see go, she was my fave vamp after angel