If there's anything I prefer more than "shonen" manga (action-y, made mostly for boys) like Naruto and Bleach is horror manga.  I'm not talking about Death Note or even High School of the Dead, but manga created by Junji Ito.  

    The first thing I read was Uzumaki, which is about a town cursed by the "spiral". It made me have a fear of snails for a short while, but it almost made me want to read everything he's ever created. I managed to get the Junji Ito collection and read other famous works such as Tomie and Gyo.

    Other horror manga I've read not created by Junji Ito is Parasyte, and it had to be one of the best ones I've ever read. It's been a while since I've read it, but I remember it being about parasitic aliens. Although it was rather violent, it had a hidden meaning in the end. 

    If any of you want to read something other than shonen or shojo manga and are into scary movies and the like, I recommend reading horror.