I've read alot of manga and most of the names I don't remember (since I'm not originally Japanese) and most of them are one shots. At this point in time I'm not really looking for an incomplete series as I do not have the patience to keeping up with chapters when sometimes it might take a while for a scanlation to come up. By that time I forget what the story is about.
Anyway, I've looked through so much in this site for something new and interesting. A twisty storyline (mind you not something weird) and no cliche shoujos/shounens oh gosh if I see another one of the millions out there I will...ha ha. I'm really bored right now and I'm craving a good solid series. But on a brighter note, something that can get me hooked and has a side romance in it or full romance in it. Stuff that I've really enjoyed has been (mind you alot of the manga here is not complete yet (+), but I just got hooked onto it because it was so good!) :
Sorry, but in what way is absolute boyfriend like Kare Kano One is about a robot and the other is about... well, top students. -_-"
Hmm, I recommend Mars. It's sypnosis might sound cliche but when you read past the first volume you find it's really good and the psychological aspects are really well done. Aishiteruze Baby is good too, and Kodocha. These are all completed series.
Try Kaguya Hime if you are looking for something really different, it is defin. out there but has a pretty fast-paced story line, others you might wanna try are Basara or 7 Seeds both are more action-based shoujo mangas, another is Mayonaka no Adriane which has suspense and mystery built into it's plot.
I forgot to mention that if you like Demon Flowers try Baku as well as Asian Beat or the Demon Ororon all by Hakase Mizuki