I'm watching 'Love in the Moonlight' now and just love the way Park Bo Gum smiles - makes him more handsome! In my opinion, other actors with winning smiles are So Ji Sub, Choi Si Won, Kim Woo Yin. Who are your favourites?

Lee Joon Gi
Jin Young in Love in the Moonlight ^_^
Bogummy too!!
Haruma Miura in Kimi ni Todoke
My fave smiles are Byun Yo Han's and Gong Hyo Jin's eyesmile :)
Park Bo Gum and Lee Hyun Woo ( Realised they happened to be the look a like pair haha guess there's some consistency in my liking ) 
Lee Jong Suk and Shin Min Ah. 
Park Hae Jin, Matsumoto Jun and Yang Yang are just a few that slay me with their smiles.
Fujiki Naohito
Lee Jin Wook
Lee Joon Gi
He gets irresistible when he smiles
Hyun Bin & Seo In Guk (I must have a thing for dimples)

Shin Min Ah, Park Min Young.
There are a few.... But top 2, w/ brightest, cutest, and most stunning smile,  would have to be:
PARK SI HOO .... and .... BI RAIN

Also, another stand out: Yo Jin Goo 
Jasper Liu. He's really charming when smiling. ❤
Another one is Sakaguchi Kentaro. :)
Yoo Seung Ho
Park Bo Gum
So Ji Sub
Seo In Guk
Ji Chang Wook
Seo in guk
Ji chang wook
Lee jun ki