Which dramas have characters that are like this? Not the usual neurotic, dumb, or catatonic.
(I don't mean characters who are suffering from a mental disorder but rather the personality)

It's sad most writers do a disservice to the actors and actresses in this industry creating 
roles like these for them esp the dramas. Just trying one I can enjoy watching without being 
annoyed at the characters. 
Hong Seoul from Cheese in the Trap is fairly normal.  
A Man's Story - despite the title, it has two really fascinating female characters.  Definitely not neurotic, dumb, or catatonic.  More of a revenge type, though, not much romance, so I'm not sure if that's what you're looking for.  Also can't guarantee you won't be annoyed with one of them, but it won't be because she's stupid, just a bit on the opaque side. :)

Also maybe Dal Ja's Spring?  She's pretty normal, and that's one of the few romance-type dramas that I made it through and still thought was worth watching (rare for me).
Faith? I don't know if you'll like the supernatural and historical mix, but I was never really annoyed at the characters. They did their roles without it being too much. Plus I loved how real the female lead was. 
I feel you, the dumb, neurotic female character cliché really annoys me :/

I second Faith, and would also recommend another drama the female lead actress has played in: Angry Mom.

A few others dramas i would recommend:
I hear your voice
Sassy go go (main played by Jung Eun Ji)
Reply 1997 (main played by Jung Eun Ji)
The Producers (main played by Gong Hyo Jin)
- The Master's Sun (main played by Gong Hyo Jin)
I remember you
Scent of a woman

Btw, I rated all of these dramas quite highly^^ I guess it's the element of a good drama, if the female lead is an interesting character :)

Hope it helps! :)
Thanks for the suggestions so far, checking them out! :)
Arang and the Magistrate
Coffee Prince
Falling for Innocence - HE's a bit of a nutjob, but she's normal.
Ho Gu's Love -
Me Too Flower - She's actually mental, with some anger issues, but she's not a wide-eyed Candy
Sungkyunkwan Scandal
The Suspicious Housekeeper
Female lead with strong personality:
Secret Garden
Marriage not dating
Good bye mr. black
Six Flying Dragons
Hmm.. It's Okay That's Love, Secret Garden, Coffee Prince, The Master's Sun, etc. All good dramas ^^
Just finished history of a salaryman. She is very strong (and quite foul mouthed which is funny) the second female lead is a tad annoying but the show was OK. Not as funny to me as some make out but the beak yeo chi character totally made the show.

Edit: I've just realised the Mo GA bi character is not the second female lead but she plays a huge part in the second half of the drama. The second lead woo hee is actually also pretty strong in terms of her personality but her decisions are pretty weak
Hong Seol from Cheese in the Trap was one of the few leads that I could really see myself.
@cityhunter83 and @Pelin 

I agree with you two..
+1 for faith.

Anything with Park Min Young is the female lead, the role will have substance and accomplishments and be a strong woman.  She's my second favourite actor just because of that.  I wonder if it's because she's been typecast or if she deliberately chooses strong no nonsense normal roles.  I really admire her. 

The female lead in Beethoven Virus is relatively normal, no major craziness.

The female lead in I hear your voice is a good strong normal character too.
Oh My Venus & Another Miss Oh !