You should definitely watch the following NO MATTER WHAT!!!!
MY GIRL (I loved the music and the actors! Amazing performance from every main and supporting cast!)
LIE TO ME (Amazing cast and performance! Hilarious and sweet!)
CITY HUNTER (AWESOME music, story, and cast! Loved every part of it!)
49 DAYS (This is bit of a melodrama but the story is amazing and so is the cast!)
HANA KIMI (ALL VERSIONS) xD (I honestly loved the Japanese version better but i also like the Taiwanese one too! )
I also recommend "To the Beautiful You!" It's another version of Hana Kimi but it's different and awesome in it's own way! It's Hilarious!
And another must must watch is Iljimae!! It's amazing!!! From ep 1 to ep 20! just awesome in terms of music, acting, story, etc.
oh and SECRET GARDEN! LOL now that's something i think everyone should watch! it's hilarious and beautifully amazing!! Love the scenery, the actors, the music, and the acting! ^_^
(excuse my obsessive behavior! but you must watch these!!!!)