Empress Ki
Healer
Kill Me, Heal Me
Cunning Single Lady 
Heirs
Cheese in the Trap
I cant pick one, but its a triple tie among:
misaeng
signal
healer
@Meg, you have good taste in dramas!!!!
Joy, thank you! Hopefully the list will get longer soon :D
my fav k-drama list is:
1) strong women doo bong soon
2) my father is strange 
3) playfull kiss
4) healer
5) my secret romance
6) my love from another star

C-drama list is
1) love O2O
2) Eternal love
3) Boss and me
4) Love me if you dare

Thai fav drama list is
1) full house
2) kiss me
3) once upon a time in my heart
4) ugly duckling the perfact match
5) wanna be a superstar

taiwan fav drama list is:
1) devil besides you
2) just you
3) refreshman
4) Fall in love with me

fav j-drama is one and only that i like so much is my little lover minamikun

1 LOVE RAIN
2 The Woman Who Still Wants to Marry
3 Heartstrings
4 Mary Stayed out all Night
5 You're Beautiful
1.you are beautiful 
2.healer
3.rebel who stole the people  (currently watching this and I love it so much)
4.innocent man
5.bridal mask

I'd like to add Kill Me Heal Me...my god that was such an amazing show
God's Quiz was my favorite one with 4 seasons!
I can't put these in certain order because I like all of them :D I will just try to describe them shortly
- You're Beautiful: it was the drama that really got me into k-dramas, one of the first dramas that I ever watched
- I Hear Your Voice: good plot, fresh, very interesting, touching and the story is moving forward without many filler scenes and the main female lead wasn't annoying and poor as in many other dramas
- You Who Came Fom the Stars: very good, so interesting, well-written plot, good actors, very touching and I loved the hot badass guy (can't remember his name lol)
- Love Rain: such a tear-jerker for me + I love Jang Geun Suk, beautiful soundtracks
- Coffee Prince: so cute and fresh, a little older drama but "a classic"
- Secret Garden: very funny, cute and a little awkward but definitely a really good series, another "classic"
- Scent of a Woman: a little more mature, touching, very realistic and just so good drama
- To The Beautiful You: funny, cute, heart-warming, light-hearted and pretty easy drama to watch, plot is a little cliche but it doesn't matter

From the classic old dramas definitely :

Winter Sonata (2002)

Which Star Are You From? (2006)

The Snow Queen (2006)

New-ish dramas :

Healer (2014)

Cruel City (2013)

City Hunter (2011)


If I had to pick one, it would be Secret Forest/Stranger.

It's Okay That's Love

Dear My Friends

Age of Youth

Moon Lovers Scarlet Heart Ryeo

Nine: Nine Times Time Travel

Ho Goo's Love

Padam Padam

Something About 1 Percent

Goblin

Its OK That's Love

hmm.. hard question... it depends on my mode that my list of faves in k-drama changes.. *o*/ currently the situation is like this:

1. Strong Woman Dong Bong Soo (if you are a BEGINNER in Korean world, then it's NOT for you. cause you probably won't understand it and it will be weird for you- especially the comedy part. if you are already accustomed to Korean world and dramas - it's an masterpiece! XD combination of genres, great cast, fantastic humour, sarcasm, suspense,supernatural elements, meaningful story and with beautiful romance, and all characters are wonderful, not a bit annoying!)

2. Golden Rainbow (one GREAT long slice of life with a lot of drama, full of everything, complicated connections between the characters and their life, really teachfull and emotional. I just couldn't stop after starting it, and I fell in love with all charas)

3. 49 days (it's various! it has romance, comedy, but it's meaningfull and dramatic and it has that bitter feeling of mixed emotions mainly of loss hope and the fact that time is passing even quickley than we can predict and that we need to cheeris every moment in this life. you can't predict where the story will go, cast is great! chemistry beautiful! music nicee! every scene is nicely done.I didn't want to skip anything.)

4. Emperor of the sea (One jewel of old historical slice of life k-dramas!! complex story and chains between characters and their lives. Based on historical persons and facts, placed in old history of Korean peninsula, where there were kingdoms, and when China has the biggest word on Asian continent rulling in every field. Story of slaves, of pirates, of robbery, of gladiators, of travel, of trading,of manipulation, of war, of wine, of martial art, of love, of friendship, of endurance, of willpower, of history! great music! fantastic old cast! gosh I fell in love with everyone! and bad villains were great villains! watched with my mom, and we were breathtaked for the whole series until the end. It has a lot of drama, it has beautiful sceneries and scenes, it's slow and emotional at most parts - that old wonderful feel that I really respect and not mostly of nowdays fastly flashed and rushed story series. so if you want one long hard beautiful heartbreaking learnful and bitterly romantically colored historical slice of life drama I recommend!)

5. Painter of the Wind (one romantic historical series of art, friendship and love. Beautifullll music! scenes and cast! interesting setting and based on historical real story and person)

6. The Greatest Love (one old great comedy romance! XD about korean superstars and their lives, romance,difficulties and above all interesting story with amazing comedy - I cried at the same time cause of laughing so hard and feeling also for sad moments of leads. Older one. It woldbe nice if you are accustomed to k-pop a bit to understand the point of the story going and problems of charas)

7.  Cinderella and four knights (modern korean version of cinderella! GREAT one in my opinion! refreshing and for those times when you want to watch many beautiful men in one package of series with ok and acctually pleasurable main female lead who knows what she wants and is good person- mentally stabile without whinning the whole time! good comedy! GREAT MUSIC!! I like the whole cast, and story going is interesting~ I felt the chemistry and gosh I must say I rewatched it 5 times in a row in one month XD I was soooo in mode for watching this~)

8. Ghost (my fav korean drama about hackers, manipulation through money, power,. goos suspense and the bad guy is really making you feel like there jumping on the TV and telling everyone that they are wrong *o*/)

9. The World That They Live In (nicccee slice of life! about those who make our loveable korean drama series without which we wouldn't enjoy life that much :) about actors, manageers, directors, scenarists, stuff, music directors etc.. great cast! without too much 'boilling in blood', I mean it's slow and learnful, for those times when you just want to relax and feel the slice of life)

10. Secret Garden (haha XD this is my alltime favorite k-drama! for any mode. It has everything, and above all breathtaking moments, memorizable characters and their moments, amazing comedy, great cast!, wonderful music which catches your ear immediatelly!, it's light, nice story like a tale, action, drama and beautifullll romance with hardcore main female lead who is humble stunt woman and an arrogant charismatic funny rich male lead)

11. The Three Musketeers (I think that everyone knows the story of THREE MUSKETEERS which after Dumma's writting it became 'evergreen'. this is korean historical version, put into their time and place in Joseon dinasty. Great cast, nice story line, good music, and gosh I thought it will be borring but me and mom enjoyed it till the last episode :D )

12. White Christmas (one of my faves in psyhological, thriller related drama series from Korea. Students, winter vacation, murder, killer, etc..it's really good, short one if you want something darker, and meaningful)

13. Deep Rooted Tree ( I'll just say = this is the series about Korean letters. wonderful cast, story, characters, one jewel of historical great drama, it's hard and has tragedy-like the most historical ones)

14. Dream High 1 (uhh!, about schoool, arttt, and musiccc! youth and world of making it into art field :) also about teachers and their struggles and talents and passion and jealousy and stars..light, dramatic, artistic, with goood OSTs and cast!(if you listen kpop-you'll melt cause of cast xD) first season is masterpiece! and second one is for me failure,so I recommend in my stand just 1st one for watching firstly^^)

15. High and Crush (haahh XD one of the best short web dramas about romance! funnnyyy to the core! light, nice romance - I like those ignorant main lead bastards who just after falling in love start to transform, and ok female lead~ whole cast is COOL!)

16. Bad Guy (it's really dark, dramatic, tragic, hard, emotional and uhh.. Bad. really bad. I don't like the ending >< goshhh it shouldn't end like that.. but I like it that it's maybe slightly open so watchers can end it on their own way. About treason, rich families, missunderstanding and revenge, with bitter romance)

17. Love Rain (ahhh I love this one ^^ that good old times feel! 2 settings - one is in our modern world, and another one is in those beautiful old times when our grannies were young when the world isn't soo rushed and occupied with technollogy and speeding the time. Wonderful music! it's romantic, sweet, bitter, lovely, dramatic, about photography, plants, art and just RAINNN :3 the main Jang Geun Seok - I like this role of his the most!)

18. Fugitive: Plan B (I'll just say for this one - Detectives, Bi RAIN, suspense, great delicate comedy, mafia, political corruption. I just everytime when I want some good but light feeling action without too much drama and tragedy - switch to rewatch this greatness XD above all in the OSTs are included MBLAQ - my fav k-pop group from old ones which is also kpop group supervised by RAIN personally at start before his departing to army and selling the company ><)

19. Soulmate (interesting old slice of life, romance, and lives of the couples and people connected between themselves in some way. it's funny and slow, and can teach about understaning of occasions and what other person feels or has on mind and you can missunderstand it because of yourself. I like the old cast! :3 and that old feel of korean drama~ if you want to acquire one old feel korean drama about relationships)

20. Warrior Baek Dong Soo (historical one, about legendary swordsman. it has uhhh, great cast! endevouring story! scenes and music are perfect!!! it has martial arts, romance, friendship, bandits, politic, corruption, army, treason, pirates, and if you like BL moments also for those who want to see it that way ;p )