Cruel City and Go Ho's Starry Night
Hanzawa Naoki and Ikebukuro West Gate Park
Healer 
Queen In Hyun's Man 
Splash Splash Love 
stranger
chief kim
missing you
beautiful mind
princess's man
Love Me If You Dare and Splash Splash Love .
Omg, I have a couple to recommend :D If I had to choose one, I'd probably go with Fight for my way. The other ones are: My P.S. Partner, The Master's Sun and WFKBJ. A lot of your PTW items are on my plan to watch list, too :D
I'd recommend Tunnel! I thought the characters were very well-written, and the drama itself was an enjoyable watch.
Signal!! if you liked Tunnel, this one is still better!
Outside of the ones I've recommended, Solomon's Perjury, it's on my PTW too and a pretty high priority.
you should definitely try 38 Task Force! No romance, but it's an excellent crime/investigation kdrama (so underrated). ;)
You absolutely have to watch Kill Me, Heal Me!
Chicago Typewriter, by no doubt!
Now that you've started Cruel City, I'm going to have to give you Secret!