Lolth. The conversation sprung forth from questions about the drow hero and protagonist, Drizzt Do'Urden. This was probably in early 1992.
Much like Mindflayers, Lolth's machinations fired my imagination, but I wasn't much of a novel reader in those days and couldn't get into R.A. Salvatore's books.
However, that Christmas the Menzoberranzan Boxes Set for ADnD 2E came out and it found its way under my Tree (it was my first DnD Box set, too). It was an interesting snapshot of drow life and their servitude toward their Demon Queen of Spiders.
I found drow society intriguing because it was a matriarchy...which when looking at the reproductive
As I've mentioned before, I ended up having Lolth tempt a player character in the first DnD module I ran. I just found her a great foil for my players. In my mind she was smart, cruel, beautiful, deadly and her children...the dark elves were nasty reflections of those terrible traits.
Its hard for me to think of more iconic villains for DnD to this day.
Judging by their popularity in fiction, I doubt I'm alone.