Here's the list of top rated historical drama's, what's your number one favorite of all time so far and why?

- Nirvana in Fire     - Three Kingdoms  

- Six Flying Dragons     - Gu Family Book

- Battle of Changsha     - The Disguiser

- Empress Ki     - Rooftop Prince

- The Bridal Mask     - Jumong

- Jewel in the Palace     - Legend of Chusen

- Moon Lovers: Scarlet Heart Ryeo     - Deep Rooted Tree

- The Princess' Man     - The Journey of Flower

- Queen In Hyun's Man     - Princess Pearl

- Comrades     - Sungkyunkwan Scandal

- Queen Seon Duk     - Warrior Baek Dong Soo

- Love in the Moonlight     - Faith

- The Moon that Embraces the Sun     - Arang and the Magistrate

- Dong Yi     - Chuno

- Iljimae     - Hong Gil Dong

- King's Daughter, Soo Baek Hyang     - The Flower in Prison

That's hard..Between Tree with deep roots,Princess Man and Chuno... I will choose CHUNO coz the story and fighting scene was incredible.. :)
Empress Ki hands down. All of them are great but Empress Ki is definitely my favorite because I never stopped loving her character. She started out awesome and then just got awesomer even when I didn't think it possible. I never got bored with all the political strategies and the music was epic. Over all I thought it was just a brilliant story and well directed. It hit me right in the feels. Jewel in the Palace definitely came close to second though. 
I don't know why people didn't watch Jackpot but this was like one of the only dramas I watched without miss some episode!!! amazing actors, and plot. And well carried. 
From your list, Sungkyunkwan Scandal. It's a very good gender-bender and romantic comedies are unusual for period dramas.
And I'll also add Painter Of The Wind, it's the most beautiful period drama to me.
Out of all these dramas, I chose Queen In Hyun's Man. I rewatched this drama so many time. I love the chemistry between the lead actors. This will always be a classic drama to me. It's romantic, historical. There's action, mystery, politic and more... It's where you would find most of the genres in it and they fit so well together. I did not get annoyed or disappointed from the beginning to the end. It has a beautiful begining and a beautiful ending.
@bambamby I totally agree about Jackpot.  It was a great story, really well acted.  I almost dropped it in the first couple of episodes because of the all the hysterical screaming and crying of the older actors but once it settled in it was really, really good.

My favourite historical drama is Faith.  Honourable mentions to Six Flying Dragons and Iljimae
My favorite is Arang and the Magistrate. I totally fell in love with Lee Joon Gi in that drama! ♡♡♡♡
The Princess' Man
Sungkyunkwan Scandal
Jang Ok Jung live in love
Queen In Hyun's Man
Moonlight surrounded by clouds
SHR is okay 
Oh man, so tough. I'd have to say Dong Yi, although Empress Ki is a close 2nd. I loved her character so much, and I loved the plot! 
The Princess' Man .... #1 ... story, writing, directing, OST, Cinematography, character development, balance b/e history/romance/action/politics, Acting, etc..etc... all excellent!.... and the best female character!

Next are:
Deep Rooted Tree
Battle of Changsha 

NOTE: I have YET to see.... Nirvana in Fire ....  Six Flying Dragons .... and .... Jewel in the Palace ..... I'm sure they'll be great!!
I've watched many historical dramas but nothing could beat Empress Ki from my heart. The story was unpredictable and fast-pacing. I loved the complexity of the main leads, scenery, music and costumes. Battle of Changsha came close to the second. 
Daebak- Jackpot, the Royal gambler
@crazy_duck bingo!  it's really freaking good and no one watched it except JGS fans.  It's really really good.
Daebak had the best King ever!!!