1. Darth Maul
One of the most iconic and popular Sith Lord of the Star Wars universe, only third to Darth Vader and Darth Sidious. Darth Maul is one of the unique and qualified character happened in the Prequel series and the Clone Wars, he was once an apprentice of Darth Sidious. A sinister and calculating character, not only a great warrior, king of Mandalore and Dathomir, leader of Shadow Collective crime syndicate. He was so powerful with the Force that he even survived being cut in half.
2. Qui-Gon Jinn
His way of the Jedi was always the best, and he is the one who trained Obi-Wan Kenobi, and later he even shared his Force knowledge with Grand Master Yoda, he is one of the iconic faces in the Star Wars.
3. Emperor Palpatine
One of the most powerful Sith Lord in the history, master of Darth Maul, and another iconic character for all Dark Siders. Galactic Emperor.
4. Mace Windu
Just like Darth Maul, Mace was one of the unique character in Star Wars, and his fighting style Vaapad was my favorite and his strong will in the Jedi Council.
5. Darth Vader
The most popular character in the Star Wars, and number one face. Most time I find him overrated because of his fanboys, but it is still fine for me.
6. Darth Plagueis
The wise. He is absolutely one of my favorite Sith Lord. He was one of the most powerful Sith, and only killed by Sidious in his sleep. Powerful enough to use the midichlorians.
7. Obi-Wan Kenobi
One of the most powerful Jedi Knights in the history, and master of Anakin and Luke. I like his saber skills, and he is wiser than most of the Jedi.
8. Mother Talzin
Mother of all Dark Siders. One of the most powerful dark side user ever, extremely powerful sorcerer and biological mother of Darth Maul.
9. Darth Krayt
A'sharad Hett, who manage to survive for a very long time from the Clone Wars, and kicked ass in the future as a Sith Master. Powerful Sith Lord indeed.
10. Savage Opress
Sith apprentice of Darth Maul, former dark jedi learner of Count Dooku, and a powerful warrior from the Clone Wars.