What I should watch?

it depends on what kind of drama do you want to see.. if you want to cry a lot,,i suggest 1 litre of tears, 49 days, and koizora (not the movie..drama only :P)..but 1 litre of tears comes first.. :P if you want a light drama, i choose dream high, nodame cantabile, the greatest love, and lovely complex.. but nodame cantabile comes first.. :P if you want something that give you all kind of emotions,,then i choose king2hearts..it's a masterpiece :D and if you want to see a lot of kisses, then surely it's i need romance.. :P

you hav e alot of great ones on your ptw list..but you must see MARS :D

Dream High and MARS. Dream High if you are in a good mood and need a fluffy teenager drama with music. MARS if you need a drama with depth which tackles serious problems.

Oh! Sorry. I forgot. Actually I'm watching City Hunter and it's so so so awesome! MUST SEE. Besides I like actually airing drama 'I do I do'. I'm totally addicted. I can't wait 5th episode.

Before I start I must say that these recommendations are based on my preferences, apply to the series I've finished/entered in contact with from your PTW list and I don't expect you to agree with me.

It might help you create an opinion though and you'll make a decision on what to watch next.

Must see series:
Bad Guy - revenge was never so sweet, this series has everything. You'll feel pity, anger and emptiness for the characters. You might even cry.
City Hunter - I have to admit that some characters annoyed me and I skipped a bit of it, but it was a great series.
MARS – The manga is darker but the live-action is also good. Definitely a must-watch.
My Girlfriend is a Gumiho – This series is just too cute but also dramatic.

Series that are very good but not necessarily must-see:
Nodame Cantabile – Silly girl/ serious guy/ funny situations. A fun series to watch.
Dream High 1 & 2 - I liked both series, the story is more intense in the first one. I loved the complexity of Sam Dong from DH1 and Rian and JYJ in DH2.
49 Days - because the characters are pitiable. The ending will get you.
Prosecutor Princess – I had moments when I wanted to strangle the main girl for her immature actions and I felt pity for the others for having to stand her. The series is very good.
Autumn's Concerto - if you're looking for romance/dramatic situation. Couple problems. Has a lot of cliches and is over the top at times, but it's good.
Buzzer Beat - if you're not a fan of slow development of events don't watch it, some people find it boring. I'm a fan of real-life situations that are not forced so I liked it. No such thing as love as first time, love just grows on you.
Love Buffet - I loved this series. It made me remember Peach Girl (the anime/manga). In life we can't know for sure how and who to love and it's all about "the right person at the right time". I felt the story real, maybe because I'm indecisive so I could relate to the main girl.
Koizora (series/movie) – A good series of the illness/drama genre. It caught me a little by surprise, I even shed a few tears. The movie is just a review of the series so you can skip it.
Kimi ni Todoke/Lovely Complex - Watch this series only if you've seen/read the anime/manga. If not, it's better to avoid it. This applies to live-actions in general !
Protect the Boss – Funny situations, silly guys and a tomboyish girl. What could be better than this situation?! Comedy/romance.
Prince Turns To Frog – Taiwanese series are bad in general but this one was a lot of fun. Let's forget the cliches and just enjoy the series.
Love Me Not(movie) – Combine two cliches and you obtain a lovely movie. But not in a bad way, it's actually good. I loved it!
Sorry I Love You – I can't remember well (watched it a long time ago) but I know for sure I was dissapointed about some things in this series. Other than that this series is really good.
1 Litre of Tears (movie) - Just watch the series! It offers more information and character development. The well known cliche of terminal illness and love. But if you like this type of stories, then it's good.
Flower Boy Ramyun Shop - Has a lot of funny situations. I'm not a fan of reverse-harem series but it was enjoyable.
The Greatest Love - I loved the main guy, for me he made the whole series enjoyable.
Take Care of the Young Lady - The bodyguard was my only reason to finish this one, the main leads interactions were too funny. It's quite similar to My princess.

Good/fine:
9 End 2 Outs - if you're not a fan of frustrating situations, avoid this one. Don't get me wrong, this series is one of my favorites but it can become annoying with all the twists and turns. Even I skipped a little.
Classic(movie) - As the title suggests, it's a classic story of dramatic love of the past. Nothing new but it's nice.
Gokusen - It made history. MatsuJun is at his best in this series.
Goong - Can be boring at times but it's good. The cultural elements are breathtaking. Dunno if you'll like it though.
I Need Romance – Cheating, old habits, loving, long relationships, hurt, new loves, old flames, stupid decissions and regret. This is all that describes the series..
Himitsu no Hanazono – I was enraged when the lead girl chose different than I expected. Why? I kept asking the stupid girl why she was so stupid. Was she blind or something? Other than that the series is actually good.
Love Rain – Past or present, old or new, the series is good but kinda cheesy. I got tired of all the unecessary dramatic situations after a while.
My Fair Lady – It had it's funny situations but not something I would really recommend or see again.
My Girl – An overrated series. It's not that great, actually the situations presented aren't new or better than in other series, still a good watch.
Do Re Mi Fa So La Ti Do - Amusing moments, cliches and love. It's a bit silly so it's better to watch it if you don't have anything better. Good for a rainy day.
Lie to Me – Another example of good series that lost it's way. Such a shame, it also has a great cast. It can still be watched though.
Save the Last Dance for Me – It's good. I've seen series with similar plot so it didn't impress me so I felt a little bored but don't be mistaken, the story is well played.
Smiling Pasta – I had to watch it two times because of Cyndi Wang, but now she grew on me and I could enjoy the series. I felt she was emotionless but once you get used to it, the series is quite good.
Tumbling - A cute series but I felt that some situations were exaggerated.
Why why love - Is like Devil beside you, same cast, similar situations.

Series I haven't finished yet:
In Time With You - The best role of Ariel Lin. Great chemistry, offers a mature feeling. I plan to continue it soon, the first episodes are good, I love the main couple. Hope it maintains its rythm.
Easy Fortune Happy Life - Seen just the first episodes, it was fine and yet I hesitated to continue. I don't plan to see the rest any time soon. I'm positive I can find better series.
King2Hearts – The first episodes were really good, I'll continue it when I have time.
Let's Watch The Meteor Shower – The worse adaptation of Hana Yori Dango, awful series. I won't continue it soon or ever.
Miss No Good – Seen the 1th episode and Rainie's character annoyed me but I'll give it a second chance.
Absolute Boyfriend(Taiwanese) - Koo Hye Sun's acting ruins the series. As good as Jiro plays his role, KHS manages to make you drop the series with her stupid facial expressions. Too bad though, the manga is really good and the Japanese series compared to this one is masterpiece.
Smile, You – The first episodes were good, it remains to be seen about the rest.

DON'T WATCH (or watch at your own risk)
Manny - has a good start but it gets lost on the way. I felt sorry for this one, I actually loved it in the beginning.
A Frozen Flower - The plot is interesting but it could've been better. I really expected more. If you like it thought you could also try Ohoku as it's similar from many points of view and more complex.
Cinderella's Sister - An expressionless girl and a silly sister, dunno why some people like this series, I found the plot annoying most of the times. I kept asking myself why I shouldn't drop it.
Corner with Love - Why ? Why are most Taiwanese series so bad ? I'm disappointed. From the plot you actually expect something good, then boom, you're offered some rubbish.
Drunken to Love You - Such a great start, I was sure that I'll include it in my top 5 then it all went downhill..Typical "good story gone boring" as it came nearer the end.
Marmalade Boy – It's not worth it! The story is good in the manga/anime but in the adaptation it seems like they made a parody. Bad acting and awful storyline.
Please Teach Me English(movie) – It could've been worse..I actually liked it, it had some funny moments. The teacher was fun and the main guy entertaining but if you can avoid it, you won't miss a thing.
Peach Girl – First of all we should understand two things : Taiwanese dramas are known to have bad acting and the series is old! Other than that, the series is better than I expected, it could've been so much worse (Marmalade Boy).
Romance Town – It was actually interesting in the beginning, I was eager to watch more and then the unexpected happened, the series turned for the worse.

After looking over your whole list I see you enjoy live-actions, then I can recommend you (series that aren't above) : Arakawa Under The Bridge, Attack No.1, Futatsu no Spica, Jigoku Shoujo, Kurosagi, Liar Game, 20th Century Boys, Antique Bakery, Be-Bop High School, Dragon Zakura, Fuma no Kojiro, JIN, Ikebukuro, Nazotoki wa Dinner no Ato, Yankee-kun to Megane-chan, Yasuko to Kenji, Beck, Crows Zero, Death Note, Drop, Samurai High School, Solanin, Yukan Club, Bloody Monday, Cat Street, RH Plus, Princess Princess D, Tamra The Island, Moteki, Volcano High, Yamada Taro Monogatari, etc.

Must see dramas: Boys before flowers The princess' man City Hunter Personal Taste Flower Boy Ramyun Shop The Moon that Embraces the Sun Scent of a woman Sealed with a Kiss` 49 Days Rooftop Prince Sungkyunkwan Scamdal Hooray for Love Shut Up Flower Boy Band Vampire Prosecutor Protect the Boss History of a Salaryman Autumn's Concerto