My personal favorites are the 1795, 1840 and vampire versions of Angelique. I especially liked her [spoiler]as a vampire...
talk about irony, she tried to return the vampire curse to Barnabas and instead SHE became the vampire instead....[/spoiler]
In 1795, we see her change from lovesick but determined houseservant to manipulating, vengeful witch....very fascinating to watch.
I liked her in 1840, she proved she could be evil AND good....evil when [spoiler]she turned Roxanne into a vampire and tried to to the same to Julia, but good in finally removing the curse from Barnabas for all time and helping to clear Quentin and Desmond even though it meant putting herself at risk.[/spoiler]
Angelique was always fascinating to watch but these 3 were my personal favorites.