What kind of non-manga stories do you like to read? There are manga on every subject, it seems. If we knew a bit more about what you like normally, we can suggest manga that might be compatible.
horror - I Luv Halloween by Keith Giffin (dark comedy, VERY dark humor), Monster by Naoki Kurasawa (often makes top-horror manga lists even though I personally didn't enjoy this one as much), Dark Edge by Yu Aikawa (vampires and zombies, hard to find, though)
historical fiction - There are soooooo many manga based on this, hard to narrow it down. Especially samurai era period pieces. A good samurai adventure is Rurouni Kenshin by Nobuhiro Watsuki (although there is an element of romance to this one)
steampunk - not really my genre so hard for me to make recommendations, but Steam Detectives by Kia Asamiya is supposed to be a good steampunk series. Not really steampunk, but with that same sort of feel is Fullmetal Alchemist series by Hiromu Arakawa (I enjoyed this series, and both anime series that were made from the manga)
Last Edited on: 2/14/12 5:49 PM ET - Total times edited: 2