So I've been looking for dramas with a nice male lead (my favorites so far are I Hear Your Voice, Reply 1997 and Flower Boy Next Door), since I'm really sick of the ones where the girl falls in love with a jerk that treats her like crap instead of the nice guy. Also, I really love strong female leads. Can anyone recommend dramas like that?

You might like Marriage not Dating, female lead is dumped by her jerk boyfriend and a close friend of his steps in with a request to her, due to his own circumstances they agree to a contact relationship. Both characters are works in progress so they have a little bit of love-hate relationship, and they slowly start to have feelings for each other.

City Hunter is a little more action based than romcom but male lead is warm, kind and open hearted to female lead pretty much the whole drama. Sweet love story after their initial quirks with each other in beginning eps.
Ugly Alert
http://mydramalist.com/6827-ugly-alert
and
Jejoongwon
http://mydramalist.com/796-jejoongwon
even tho both dramas are kind of long dont let that scare you, there both really great dramas and they have exactly what your lookin for .. at least i think so.. ^.~
and
D-Day - is a great drama ( the main lead is a nice guy, and the female lead is strong ♥
http://mydramalist.com/14086-d-day
Coffee Prince
Orange Days
Pinocchio
In Time With You
Queen In Hyun's Man

MARS, Boss & Me - Not a jerk to the heroine because he's interested in her from the first
Romance (http://mydramalist.com/1900-romance-2002)
I Love Lee Tae Ri
Good Doctor
The Girl Who Sees Scents
Yong Pal
Otomen
Can You Hear My Heart
I second Boss & Me, MARS, In Time With You!!! Other recommendations: Material Queen, Rock'n' Road, The Hospital
+1 The Girl Who See Scents
+1 Can You Hear My Heart
How old are you willing to go back? 
Here's a similar thread that might give you more recshttp://mydramalist.com/discussions/recommendation-forum/24197-romance-dramas-with-good-guysHere's a similar thread that might give you more recs
Smile, You
Nine: Nine Times Time Travel
History of the Salaryman
Flower Grandpa Investigation Unit
I Hear Your Voice
what i am currently watching:
5 ji kara 9 ji (jdrama, a very sweet drama where the main guy pledges his eternal love for main girl hundreds of times haha)
bromance (tdrama, the girl and guy are best friends and its still ongoing, it's a crossdressing drama but don't let that stop u, its so sweet and tastefully done)
kiss me (thai drama, if you like itzura na kiss its the thai version, that main guy is a hundreds times nicer than the korean version trust me)
edit: also ugly duckling, perfect match (thai drama)