Any good romance manga?

Emma might fill the bill

My absolute favorite one of these is Hana Zakari No Kimitachi E (Hana Kimi). It's about a US Japanese girl who idolizes a high jump competitor. Eventually she transfers to the same school he goes to in Japan to et to be friends with him. Unfortuantely, it's an all-boys school, so she has to disguise herself as a boy to get in. It's The Best romance manga that I've ever read, and even though it's long, it is so worth reading! And on top of that, it has really nice art. Definitely a must-read.
You can read it here: http://www.mangafox.com/page/manga/series/80/hana_zakari_no_kimitachi_e/

Another one I think is cute is Marmalade Boy. It's art is probably closer to that of the ones you mentioned. It's also a bit long, but is a good length. It's about a girl whose parents decide to swap partners with another couple and move in with each other. On top of that, the other couple has a very cute son, and the story is about their relationship. It's got great humor, I laughed loads!
You can read it here: http://www.mangafox.com/page/manga/series/57/marmalade_boy/

There are loads more like you're describing out there, but these two are just a couple of my very favorites.

I'm gonna tell you some of my favorite romance mangas.

(Awesome) Please Teacher!:
Plot Summary: Kusanagi Kei, a high-school student living with his aunt and uncle, has an encounter with a female alien. This alien is revealed to be a new teacher at his school. Later, he is forced to marry this alien to preserve her secrets.

ToraDora!:
Plot Summary: A man with eyes that are so scary, so mean looking, that he's been isolated by almost everyone he's ever met. A girl who's said to be as fierce as a tiger. There is one girl who isn't afraid of him, the tiger's best friend, and as a result he's developed a crush on her. However, his only male friend is the idol of the tiger's affection. Due to a misplaced love-letter, the two team up in this odd-pair romance to help the other succeed in their love-goals.

Clannad:
Plot Summary: Tomoya Okazaki, a third year high school student reputable for his low attendance and his delinquency with his friend Youhei Sunohara, befriends a girl named Nagisa Furukawa, who was forced to repeat a year due to her illness. Having some urge of empathy, Tomoya Okazaki accepts to fullfill Nagisa's dream to set up the Theatre Club.

(Awesome) School Days:
Plot Summary: Makoto Ito rides the train to and from school every day. However, at the beginning of his second term, he falls in love with a beautiful girl that also rides the train. Unfortunately, she barely knows of his existence. Her name is Kotonoha Katsura, and though they attend the same school, they are not in the same class. In an attempt to catch her eye, Makoto enlists the aid of a close female friend of his: Sekai Saionji. She helps him, despite the fact that she--unbeknownst to Makoto--is in love with him. Thus the three are bound in a love triangle of life changing proportions.

Skip Beat (2008).