Favorite shōjo series?

Hiya! I'm not sure how active this group is, but I figured I'd ask what everyone's favorite shōjo series is? Be it manga or anime ^^ Let's all have fun gushing about our faves!

My own personal favorite is Sailor Moon -- I love both the manga and the 90s anime (haven't seen Crystal beyond the two movies, one of which I watched in theaters in Japan! ^0^); I think each of them offers something that the other does not; the manga has absolutely gorgeous art, and the anime has character moments that I feel the manga doesn't always deliver on.

I also really, really love Nana! I watched the anime a few years ago, and I'm catching up with the manga -- it's just such a well-written story with so much depth to the characters! I could talk about the series for ages, hehe ^^ But I'm gonna stop myself here; I'd love to hear about all of your faves!