Last Game - my most fav shoujo
Beauty Pop
Oresama teacher
Gekkan Shoujo Nozaki-kun
Natsume Yuujinchou

and a new Namaikizakari
oh i realized i love shoujo with male lead and kuudere/dandere female lead

That's a really hard decision to make!

I really liked Hana to Akuma. It's not too short and not too long and has a sweet story (and i admit it - it made me cry in the end).

If you like shorter stories, I can recommend Hanatsukihime. It's setting is very "arabian nightish", it has demons, sweet characters and really beautiful artwort.

Soryanaize Darling also was a good read. It starts like the typical smut manga but if you keep reading you are rewarded with a really interesting and good plot.

Oh, and let's not forget Gekka no Kimi and Shinobi Life!

Also Hana yori Dango was a great read! The artwork in the beginning is horrible but improves a lot in the ongoing volumes. And even though the story has its ups and downs and sometimes drags on just a little bit too long, the story has stayed in my head and I keep rereading the manga on a regular basis.

And a big thanks to everybody who posted in this topic: I found a lot of mangas I didn't know and really want to read

My best shoujo:
Last Game
Hibi Chouchou
Kanata Kara
Natsume Yuujinchou
Orange (TAKANO Ichigo) (I think it's shojo...)
Donten ni Warau
14-sai no koi
Taiyou no ie
Lovely Complex

Mars gets my vote.

________________
I also read EU/US comics and am a librarian.
Manga-Masters, My ANN-Lists + Imdb

I love ↓
Natsume Yuujinchou
Horimiya
Taiyou no ie
Namaikizakari
Hana Yori Dango
Kobayashi ga Kawai Sugite Tsurai!!
Kamisama Hajimemashita
Kaichou Wa Maid-sama!

My faves are...

Kimi ni Todoke (It's still ongoing but it's my absolute fave )
Lovely Complex
Fruits Basket
Hana Yori Dango
Ouran High School Host Club
Full Moon o Sagashite