The Big Adventures of Majoko, by Machiko Fuji and Tomomi Mizuno, from UDON Kids. A "standout" "fantasy-adventure for youg girls," Majoko also earned points for being a manga that didn't have tie-ins with a huge merchandising scheme (cough cough, Pokemon).
Dinosaur Hour, by Hitoshi Shioya, from VIZ. This one-volume features art that "is relatively accurate but also fluid enough to engage kids with gags and slapstick."
Happy Happy Clover, by Sayuri Tatsuyama, from VIZ. "If Beatrix Potter had been a mangaka...she might have produced something like Happy Happy Clover." What more do you need to hear?
Ninja Baseball Kyuma, by Shunshin Maeda, from UDON Kids. A ninja-in-training meets the captain of a baseball team and is conscripted onto the team. Apparently "the combining of ninjas with baseball works," and "even middle schoolers are enjoying this title!"
Leave it to PET! The Misadventures of a Recycled Super-Robot, by Kenji Sonishi, from VIZ. If you didn't think a manga about recycling could be funny, then you've never read Law of Ueki OR Leave it to PET!, whose robot hero "turns out to be an inept goofball whose super powers have a tendency to make situations much worse."
Children of the Sea, by Daisuke Igarashi, from VIZ. When a teen girl's parents divorce, she meets two boys over the summer. Both were raised in the ocean. "This is a manga for teens who don't fit in," and the art "isn't limited to being shonen or shojo."
Kimi ni Todoke: From Me to You by Karuho Shiina from VIZ. Some of you will already be familiar with this since it was just made into an anime: Sawako is a gloomy-seeming girl who is often compared to Sadako from The Ring, but she's really just painfully shy. The most popular boy in school, Kazehaya takes her under his wing. Sort of like a more thoughtful "She's All That."
Pluto: Urasawa x Tezuka, by Naoki Urasawa, from VIZ. EVERYone who is the appropriate reading level or higher should read Pluto. It's just too phenomenal. SLJ says that "Urasawa uses every facet of comic storytelling to craft his tale, giving readers a fully-fleshed out premise, even for readers who don't know the original work" (Astro Boy).
That's all the manga from the list, but there are also a couple of manhwa and of course, a lot of American comics, so be sure to check out the full list!
However before he can even begin this journey he must first find his spirit companion, usually an animal, to empower him with their spirit abilities while he meets and overcomes a cast of lovable villains that eventually join up with him and help along his quest. It touches on some serious subjects liking bulling, gangs, duty to ones family and self betterment through hard work but does it in a very kid friendly way that mixes in fun battles between various Shaman Warriors and a cast of lovable characters.
If it wasn't for manga like this creating a love for the medium i honestly don't think i would be watching/reading anime and manga today.
Hells to the ya, that was my favorite anime for a long long time time and will always hold a special place in my heart, as we tend to remember the firsts in our life. Back when the only access to anime and manga i had was Dragon Ball Z on TV and my Shonen Jump magazines i bought every month i looked forward to reading the newest issue of Shaman King, Yu Yu Hakashu, Naruto and to a lesser extent the Yu-Gi-Oh when they had them as running series.