MAISON IKKOKU MAISON IKKOKU MAISON IKKOKU MAISON IKKOKU MAISON IKKOKU
Must I say more? Maison Ikkoku is possibly the BEST manga I've ever read. This is my all-time favorite story on this earth. I need to re-read it again, but my Maison Ikkoku books have been through so many hands... lol.

It's even considered an Editor's Choice, so it's really good anyways.
Hmm... I'm looking at my nearly-all-shoujo manga bookshelf and I'd say that these are all REALLY good (* ones are DEFINATE MUSTS! and # are comedies and romance):
Aishite ru ze Baby ** (those stars are in the title. Not definate must!!)
Skip-Beat *#
Absolute Boyfriend #
Sugar Sugar Rune
W Juliet *
Here is Greenwood (so-so, but shoujo...)*
Alice 19th
Maison Ikkoku *********************
Kare Kano His and Her Circumstances
Somedays Dreamers Spellbound *
Red River
From Far Away
Harlequin Pink series of American romance novels into mangas
Saikano **************
Yeah. Those are some good shoujo mangas!!