I'm looking for manga with plot, where the story develops into something deeper than it seems at the beginning. I also like manga where a relationship actually develops between a guy and a girl. Some of my favorites r D.gray man( i like the characters and how the story progresses XD), skip beat, koukou debut,fruits basket(er...), bitter virgin( not really related to the topic), FMA, and some I can't remember at the moment.
Ummm how about Beck. You can really see how the peoples personalities clash and mesh together, and there is a decent amount of romance. Its a bit depressing at times, but still a great manga. It left off at a great point too. Someone scan ch 93 and on plz!
Katekyo Hitman Reborn. The first volumes it seems like a fun and games gag manga, but eventually the dark side of the Mafia world is revealed (it takes a while thought). I wouldn't call anything in this series real romance.