Officer Shibata Taketora works in a local koban (a small police office). He may have a child-like face on the outside, but he's more serious than anyone in his pursuit of justice! With his goal being to become a detective, Taketora confronts everyday problems that happen within the town! Various incidents within the street make him chase after and apprehend criminals!

From DrCoke at MangaHelpers:

Six years ago, Tsukihiko was caught in an assassination attempt on a little girl, Sami, when he attempted to be her shield. This incident nearly killed him and the girl together, but the little girl was the daughter of an extremely powerful family. With its vast amount of resources, the family was able to keep both Tsukihiko and Sami alive by recreating both of their bodies with cyborg technology. This has forced Sami to permanently rely on wired connection to her life sustaining computer. On the other hand, Tsukihiko has become a cyborg "Knight," sworn to protect Sami from harms way.

When he first logs-on, he sees his friend fall into a coma before his very eyes. Now Kite is searching for the answers as to why, and how to save him, inside 'The World'. Based on the original PS2 .hack series, Infection Expansion (Vol.1), Malignant Mutation (Vol.2), Erosion Pollution (Vol.3), Absolute Encirclement (Vol.4).

When an object is cherished for 99 years a deity is born within that object; also known as a Tsukumo deity. Yukiji's companion, Tamakichi, is a deity; he was born from a certain item her mother left behind. As Yukiji enters Mizuhozaka Girls’ Academy Tamakichi constantly puts in a troublesome appearance. Yukiji's hopes for a good school life looks dimmer and dimmer.

Eliza's grandmother constantly destroys any approaching suitor before Eliza gets the chance to talk to any of them. Will this be her chance when she's alone and finds a cute boy in the forest with his pet... worm?

Aki is head over heels in love with a classmate but doesn't know how to confess.

From Monochrome Dreams:
Ichinose Tarou is at the age where he's really awkward about girls, but he's been chosen to perform along with a girl in a year end festival. His partner is Momozono Anne, the daughter of his father's boss, who seems to be in love with Tarou for some unknown reason. The two of them are supposed to build a snow demon and destroy it together at the festival, but Tarou would be happy to avoid Anne and do all the work alone. How will Tarou deal with this unwanted intruder in his life?

1. Kohrogi
Mitsurugi Kai is a wizard that must pass a test of character. He doubts himself due to his past. His test is to retrieve paper charms by himself. On his way, he meets Kohrogi Orine who is a fledgling singer who also doubts herself.

2. NOIZ
Hayami Shrou can see into the future of people by touching them. Two years ago he lost his parents in an accident, while his sister barely survived, but remains unconscious. He blames himself, thinking that if he had touched them and saw into their future back then, he could have saved them.

3. dZi:s

4. X-connection 2001

From VIZ:
In the not too distant future, mankind battles over O-Parts, relics from an ancient civilization. It takes a special kind of person to unlock the full potential of these remnants from the past, and a unique breed of humans known as O.P.T.s (or O-Parts Tacticians) become a force to be reckoned with. Unfortunately, O-Parts can be used for good or evil purposes.

Jio is a young boy with a tragic past who only trusts one thing in the world: money. Little does he suspect that he is actually a very powerful O.P.T., and inside him sleeps a demon of incredible ferocity. He meets up with a girl named Ruby, and together they decide to embark on a dangerous quest to discover as many O-Parts as they can. Will Jio help Ruby realize her dream of becoming a world famous treasure hunter? More importantly, will Ruby help Jio realize his dream of--world domination?!

By all the usual measures, he could be considered a pretty useless guy: a scholastic failure, an athletic disaster, and a chronic loser... but Fukuda Shinichi has one passion: cheering for others!

The 18-year-old captain of North Kanto Southern High's Cheerleading squad decides to make the most of his summer by attending cram school in Tokyo, only to find out that the whole trip was a sham! Things are looking up when he and his friend meet up with two cute Tokyo girls; too bad the girls brought them to a rip-off bar and took off! Ditched by his one remaining friend and stuck with an impossibly high bar bill, Fuku-kun's life couldn't get any worse!

But just then he gets saved by Ume, his role model and former cheerleading squad captain! What is he doing in Tokyo... and why does everyone around seem to know and respect him? Without anywhere else to go, Fuku-kun decides follow Ume to his job, only to discover that... he's a male gigolo!? Fukuda's summer of cheering others on has begun... and the streets of Tokyo's red-light district will never be the same!

Hiroshi found a broken cellphone on the street and went to a shop to get it fixed. When it got delivered to his home, he got a life-sized girl instead but it is still a cellphone. Hiroshi only wants a normal cellphone that he can brag to his classmates but he can't return this one because of the expensive return fee written in the purchase contract. This is how Hiroshi discovers the advantages and disadvantages in life of owning a cellphone-girl, which he named Eko.

From Tokyopop:

Beings who possess animal-like powers walk among humans in this alternate universe. These mysterious mutants, the +Anima, are shunned by society. Four outcasts in particular--Cooro, a boy with crow-like powers; Husky, a fish-boy; Senri, a bear +Anima; and a girl named Nana, who wields the power of the bat--search for others like themselves while trying to gain acceptance in a world cruel to anyone or anything that is different.

A young girl (Kaburagi Aruto) aspiring to become a shoujo mangaka, much to her chagrin, discovers she is fated to become a renowned hentai manga artist (thanks to a time-traveling robot named G-Maru who is also her biggest fan).

The main character Udagawa Gosuke has received his father's dojo, mainly because his father and older brother were made to commit hara-kiri. He wasn't really supposed to get it simply because he's a second son. But due to the way his pops and brother died, he doesn't have a whole lot of self confidence, so he practices fencing day-by-day at a nearby dojo. However, because the people at that dojo are asses, he soon tries to invent a dojo and a style for people who just enjoy it.

However what really sets this aside from most shounen is that the main male and female characters are actually married. (At age 15 no less!)

The girl Utagawa Shino is the younger sister of his senpai, and is a bit...weird, to say the least. She makes rabbit masks to help bring in a bit of money, although to say that she's obsessed with rabbits would be an understatement. She claims it's because "the rabbits will someday reach the moon." When Gosuke invents his new dojo, he decides to make a style of swordsmanship known as "Rabbit Style Fencing."

Souta Inui is a manager at Megapro talent agency, an agency responsible for turning young, beautiful women into stars. Inui, however, spends his time at the office ogling posters of the idols his agency manages, and has yet to bring in any new talent or take on a single client himself.

When told to go to the streets and scout talent, Inui falls and unwittingly grabs ahold of a devil girl's tail, at the same time asking her to join his talent agency. Now bound by contract, the girl has no choice but to abide by his wish, making it her goal the become the number 1 idol in Japan.

But who is this girl? Why is Inui the only one that can see her tail? Is she really a demon aged many thousands of years? No matter the reason or history, it's now up to Inui to turn this aggressive devil with a (literally) killer voice into the number 1 idol in Japan.

From Baka-Updates: Aoi Kururi is an onmyou-ji who is studying smells at a private academy. He in fact hates using onmyou magic, but when a spell is mysteriously cast on his whole class that causes everyone to wet themselves, he finds that with the warm power and sweet smell of girls' urine, his magic becomes more powerful, and he saves his class by breaking the spell. This is the story of the strange misadventures of Aoi, his sisters, and his friends.

Nagasawa Shiina is just an average 3rd year high school student until her parents' company goes bankrupt. In order to pay the bills, she sells herself into prostitution. At her first job, a mysterious masked man crashes the party... and it's someone she knows.

Akumetsu is the story of Shou, a vigilante that's out trying to straighten the corrupt Japanese Government through terrorism with his "One man, One kill" code of action.

A series of three manga tankoubon released between 1983 and 1997 that collect several one-shots written and illustrated by Akira Toriyama. The stories were originally published in various Shueisha magazines between 1978 and 1994.

The minister's aide has an idea, a project in mind to help correct the declining birth rates in Japan. This plan, so to speak, has it where Japan's youth are encouraged to form relationships. The catch is that at the chosen high school for the initial test of this is being held, the project is mandatory - the students must become intimate couples with the other students or they will die.

Based on the Chinese novel Shui Hu Zhuan, this series is about the trials and tribulations of a band of outlaws during the mid Song dynasty.

It is 1112, China is in turmoil with the present Song dynasty's government and its inability to control its own provincial officials from preying on their people. However, tales of a band of outlaws punishing these abusive officers called "Taiten Gyoudou" is spreading. Their deeds are giving people hope. It begins with an encounter between Suiren, a young village girl believing in the bandits, and "Falling Star" Tai Sou, a traveling swordsman whose skill precedes him.

* Suikoden (水滸伝) is a Japanese translation for Shui Hu Zhuan.