Wow, there is a lot to offer, but I don' know your taste so I'm just guessing what you might like:
Hana Kimi (Hanazakari no kimitachi e -it's Japanese version of course)- It's very famous, it has Oguri Shun, it's funny, might seem quite childish sometimes, but it always makes me smile, even if I'm down.
If you into Taiwanese dramas then Hot Shot or Hi! My Sweetheart or Skip Beat!
Lovely complex - absolutely cute, high school love story
Love shuffle- if you want something more mature, yet original and funny Yay! Panda!
Nodame Cantabile- I love it too much to write about it. I recommend it everywhere. It is absolutely hilarious at times- it is crazy!.
Samurai High School- It had me LOLing all the time.
Yankee-kun to Megane-chan - another high school drama, a very funny one, with Narimiya Hiroki, I really like him as an actor.
Yume wo Kanaeru Zo- it isn't very popular, but I really like it, it's about how to be happy
