I enjoyed the light & fun 7 First Kisses web series. It has a three song OST.
1. Kissing You by Ji Chang Wook. Yes, the star of epsiode 4, K2, Healer, etc, sang the theme song. Why not, his voice is good. In the press video I watched Lee Cho Hee (who played the never been kissed character Soo Jin) said she enjoyed working with Ji Chang Wook the most. The video pulls double duty as a decent series video. You get a good feel for each episode with each star.
2. Beautiful Day by Melody Day. The video features each episode of the 7 stars (though it’s only a brief seven second glimpse of Lee Min Ho at the 3:26 mark) including sippets of the extra endings as well as Melody Day singing (or at least being filmed) in the studio.
3. My Girl by Soriai and Lee Nu. Only audio. If you want to get to the snippet played every “almost kiss” head to the 1:08 mark