Drusilla is an ancient Roman name, (probably) borne by descendants of Antony and Cleopatra, and is one of the 'illa' names that are ready for a comeback, especially with its cute short form Dru.
Drusilla appears in the New Testament as the wife of Felix (twin alert?), and later made appearances in Thomas Hardy's Jude the Obscure, Wilkie Collins's The Moonstone and Faulkner's The Unvanquished. Drusilla is a vampire in Buffy the Vampire Slayer and Angel, and was a long-running character on the soap The Young and the Restlass.
An alternate spelling is Drucilla.