I agree with hopelesswriter.

Eric of Shinhwa. For reasons already stated below.

Definetly yunho from TVXQ!

Without a doubt, Super Junior's Leeteuk.
Reason: He's been through so much, yet he always has his beautiful smile on his face, and stays strong for s no matter what.
There are so many more reasons, but it would take to long to write down XD <3

Jung Yunho and Kim Sunggyu ofc. :">

I'm gonna say Yunho of DBSK/TVXQ.

I can tell Yunho cares for all of s a lot and treats them with great respect and kindness ^^ Even though a lot's happened with the group, I truly think he still cares about Jaejoong, Yoochun and Junsu and thinks about them a lot in my opinion.

I personally think there are many K-Pop groups that have good leaders for all of them, but I believe Yunho is the best leader ^^

Super Junior's Angel Leader : Park Jung Su aka Leeteuk !
reason: i would need a 200 pages book to explain! <3 <3

i agree with chocolate101 that every leader is the best leader in their own way...but if i gotta choose one...
definitely Eric (Shinhwa)
nobody can beat what he did for the group. n how he had manage to take care of s n led them out of SM together as one, the only group who lasted 15 years with no member change at all...and when they're dirt poor after outta SM, he worked his off in dramas n CFs n stuffs n get money to make Shinhwa album (didn't he even paid SM to use Shinhwa's name or something?)...mad respect dude. other leaders still have a long way to go, but for their limitations, i'm sure they all have done good for their group, and naming one over the other would be an insult. of course, exception for Eric, who really had proved his awesomeness level.

Definitely Sunggyu for me. He can be really firm and scary, but he's also really caring towards the members and he always sacrifices himself in interviews so he's bullied. Also, when he went solo, he made sure to mention Infinite in every single interview~~ :D