"Now, YOU have achance to be part of Star Wars history. Because this time, this privilege of naming the newest Sith Lord...is YOURS. One Grand Prize winner will have his or her Sith name featured as the official character name in Star Wars: Legacy of the Force: Sacrifice by Karen Traviss. The Grand Prize Winner will be recognized on the acknowledgement page of the aforementioned book."
Warnings: You have to join StarWars.com to participate. Also, the intro text on the site has some minor spoilers about Star Wars Expanded Universe continuity (namely, who the new Sith Lord is).
Well, the two Sith biggies we all know and love are Darth (In)Sidious and Darth (In)Vader, so I guess I'll call dibs on Darth (In)Festor, as in Uncle, Darth (In)Trigue, Darth (In)Corrigible, Darth (In)Ternal Revenue Service and Darth (In)stant Potatoes.