I'm trying to find a drama or movie with a nice second lead female. I've got fed up with them always being mean and horrid, and they genrally stay that way right till the last episode . I dont mind if there like that at first though as long as they've given up after about 2/3 of the drama.

Thanks 

Protect the Boss has a second female lead who turns out nice after some time and even becomes friends with the female lead!
autumn concerto has a nice second female lead
King2Hearts - She is probably my favorite second female lead.  She's Lee Seung Gi's sister, so there's no competition for romance, and her story arc was really inspiring.

Pinocchio - She wasn't vindictive, and she didn't spend the entire drama trying to pursue Lee Jong Suk.  Her scenes were often less serious, so I enjoyed her.

Pasta - She will spend some time pursuing the male lead because they have a history, but I liked to watch her journey as a chef in a male-dominated industry.  She didn't back down as much as Gong Hyo Jin's character did.  The male lead in this drama is pretty mean, though, fyi.  Not sure if you have a preference there.

The Princess' Man - Her start was a bit rough (I really thought she would be like many other second female lead, but she grows a lot as a character and you can see her motivations.  She'll complicate the romance between the leads at first, but her path leads her in a different direction.

Good luck in your search!
Doctor Stranger- I was rooting for her instead of the main female the whole drama.

King of Baking Kim Tak Goo- The second lead female was actually the nice one while the lead female was horrid.

Emergency Couple- No conniving or manipulating.

Bachelor's Vegetable Store- She might be listed as supporting character, but she was the love rival so I included this drama. 

Capital Scandal- The female secind lead in this is probably one of my favorites.
Cinderella's Sister - The second lead is the "Cinderella". She's that kind of bubbly and cute personality whom everybody likes - but also very demanding of attention. The relationship between the female leads is quite sour but gets better.
As in the second female is also interested in the main male or just unrelated to main OTP romance
.
Currently running TW drama, "be with you" the second female interested in the main male is one of the most pleasant characters I have ever seen in that position.
A Man's Story has really nice second lead girl. 
Magic (2004)
Medical Top Team
War of Money
Can You Hear My Heart is one of my favourite dramas, and the second female lead is nice, and a great character. The first five episodes or so are in the past, she comes into it later on. 
Thank you for all of the recommendations : ).
http://mydramalist.com/5184-cheongdamdong-alice  had one that fits your description perfectly.