I'm searching for a good, not too long (between 1-25 episodes long) drama, where the boy/man falls in love with the girl/woman first.
Why? I'm sick of the girls squealing annoyingly behind their backs and am totaly in love with those kind of stories since... 

I saw Boys over Flowers I guess... <3


And Kill me Heal me, Shin Se Gi fell for her first :P


If possible a gender bender Drama would be great <3

Thanks for every recommendation!! 

Reply 1997 - totally amazing series 

Sassy go go - focused more on friendship and school problems, but chemistry between main characters is great :3

Shut up: Flower boy band - imo the best drama from the flower boy! series and i loved it. initially it is more focused on friendship between guys but it gets to romance eventually :)
I secondly recommend Reply 1997, such a beautiful and amazing series that will make you cry and feel all of the feels
Reply 1997
Falling for Innocence
Cruel Romance
Lady & Liar
dream high
Tree of Heaven
Dr.Gang
Thank you all! Wow, really, thank you :)
Healer (this couple is personally my otp of otps they're so cute and the guy gets really clingy)
Pinocchio
Bromance is a Taiwanese gender bender that's currently airing, and I think it's really fun
Heartstrings (I think the guy falls for her first but I don't remember, the main point is that it's cute)
Hana Kimi is a gender bender (the japanese version is only like 10 episodes, there's also a Korean)
Full House (I personally liked the Thai version better but there's a Korean)

I don't remember who falls for the other first but are worth checking out: It's Okay That's Love, City Hunter, You Are All Surrounded, The Master's Sun
Heirs- Lee Min Ho
Heirs- Lee Min Ho
Another vote for Reply 1997 
then the on-going drama right now, Cheese In The Trap , 
I Hear Your Voice
Reply 1988
Pride
Koizora
Secret Garden
Me Too Flower
Secret
A Gentleman's Dignity
In Time With You
Boss & Me

From the recs above, I second It's Okay, That's Love.. the guy indeed falls for her first. Must watch romantic drama IMO.
Reply 1997   +1
Pinocchio   +1
Cheer Up!   +1
Secret Garden <3 <3
Oh there are alot!

Completed Dramas:
- Healer
- Pinocchio
- Ho Goo's Love
- I Hear Your Voice
- Falling for Innocence
- Second Time Twenty Years Old
- Mask
- Reply 1997

On Going Dramas:
- Reply 1988
Besides all the other great recommendations people have said:
Runaway Sweetheart (genderbender)
Love Me if you Dare
Fall in Love with Me
I Love Lee Tae Ri
Can You Hear My Heart
Personal Taste
Triangle
High School King of Savvy
Protect the Boss
1. Love Me If You Dare
2. High School - Love On (mild, but the concept "guy falls in love first" is there)
3. Murphy's Law of Love (twDrama)
4. You Who Came from the Stars (a great drama but i forgot who falls in-love first.. :p)
5. Q10 (guy obviously falls in love first) (^_^)v
6. Boss & Me (cDrama)
7. Personal Taste
8. Oh My Venus
9. Down With Love (twDrama)
10. I Hear Your Voice
11. Falling for Do Jeon
12. Devil Beside You (twDrama)
13. Orange Marmalade [cute & mild, forgot who's who again.. (^_^)v]
14. Cruel Romance (cDrama) -- Love the action scenes while we add up the romantic spices) ^^,
15. Heart to Heart (maturely cute) (^_^)v