The best thing about being a manga editor is when you get to work on one of your favorite titles. After years of dreaming that someone would release it in English (and doing a FAQ about the series, I got to be the editor of the VIZ edition of Jojo's Bizarre Adventure.
Jojo's Bizarre Adventure combines horror, mystery, humor and shonen manga battle elements, and the art is fabulously weird and metrosexual. It's one of the few shonen manga that has really memorable dialogue. Araki rarely uses a clichéd phrase, and he produces melodramatic lines that would be at home in the most outrageous superhero comics.
Author and Artist: Hideshi Hino
Publisher: Blast Books
Hideshi Hino is a great artist, but his best work is out of print; the Hino Horror Series made an unfortunate decision to reprint several of Hino's lesser works while passing up some of his untranslated masterpieces like Kaiki and Shinin Shojo (although the first few books in the series are good). But Panorama of Hell is incredible.
Special effects artist Screaming Mad George working on the English rewrite! A plot involving World War II, nuclear war, family trauma and thinly disguised autobiography! And one of the best endings of any comic ever! The only problem is that its plot elements were later recycled in other, lesser Hideshi Hino manga, such as Hino Horror: The Collection.
3. The Left Hand of God, The Right Hand of the Devil
Author and Artist: Kazuo Umezu
Publisher: Shogakukan Inc.
Kazuo Umezu is a genius. I think that the greatest artists are those who sacrifice their social lives, families and health for their work, for the "DIY and draw comics week after week until you go crazy from isolation" aesthetic. Umezu is one of these artists. I respect him because his best work has that deep, trippy and cosmic edge, because he seems to make minimal use of assistants, and because he draws the best horror comics I've ever read. (Sorry, Hino.)
I first started studying Japanese so that I could read Umezu's post-apocalyptic nightmare Fourteen. I edit VIZ's edition of The Drifting Classroom, but for pure horror, The Left Hand of God is his best, most effective manga.
4. The Rose of Versailles
Author and Artist: Riyoko Ikeda
It's a shame that this manga has never been properly released in English. (Apparently Ikeda is asking for too much licensing money.) Cross-dressing, gender confusion, revolution, palace intrigue, and the glamour and romance and tragedy and history of 18th century France... it's a marvelous shojo manga.
I admit that I prefer the early parts of the story, when the characters are still cute, to the later parts, when everybody looks like androgynous skeletons and their noses and chins are so sharp they look like knives. A great series, though.
Perhaps this one doesn't quite deserve the top honors -- the ending isn't the best and, a more general Yoshinaga problem, her art is just window-dressing for the text -- but Yoshinaga is one of the few artists who I feel genuinely tries to use manga to explore unexpected themes and aspects of human behavior. Her dialogue is without equal in manga. Flower of Life is also excellent, and her boy's love manga is good as well.
6. Everything by Moyoco Anno
It's impossible for me to pick a single favorite series by Moyoco Anno. The sadly under-appreciated, shojo fantasy-romance splendor of Sugar Sugar Rune? The hyperactive sitcom of Happy Mania, in which her art develops from a sort of crude Erica Sakurazawa imitation to a powerful, distinctive style? The sex-comedy hijinks of Flowers & Bees, complemented by a demented rewrite by Carl Gustav Horn? Heck, she even illustrated the Japanese novelization of Kevin Smith's Chasing Amy. An excellent, diverse, talented artist.
This series is very important to me, being the first anime I really got into (I discovered the manga later). In no time I, who had previously only read "serious literature" and horror novels, realized that I actually loved romantic comedy manga.
I'm also a big fan of Masakazu Katsura's Video Girl Ai. I guess I'm just too hypocritical and ashamed to put his panty shot-centric manga in the Top 10. Also I have a soft spot for Kei Kusunoki's Yagami-kun no Katei no Jijo, her untranslated gay/Oedipal love comedy, and Hiroshi Aro's sex-change fantasy Futaba-kun Change. These are the kind of things that filled my head in late adolescence.
As sleazy and repetitive as it gets at times (but it ain't as bad as Wounded Man or Path of the Assassin), this is still a great read. Kojima's artwork has a lovely, organic feel, a little warmer than the more defined and macho work of Hiroshi Hirata (who's also excellent). It's one of those long, epic stories that really transports you to another place, to the forests and towns and capitals of Tokugawa-era Japan... a recreation of an entire world, down to every detail.
9. Iron Wok Jan
Author and Artist: Shinji Saijyo
Publisher: DrMaster Publications
This manga is really repetitive and kind of inane --but I can't put it down. Apart from the fact that it is a food manga the best things about it are the savagely exaggerated artwork and the generally anti-heroic mood.
The main character constantly acts like a complete jerkhole to everyone he encounters. Everyone hates, hates, hates Jan throughout the manga, and Jan also suffers his share of humiliating defeats. This "he never gets a break and he never gives one" attitude is refreshing compared to the moralizing "I, with my omnipotent powers, am blinding you and driving you insane because you knocked over my friend's ice-cream cone" attitude of something like Yu-Gi-Oh.
Author and Artist: Go Nagai
I borrowed Devilman (along with Violence Jack, precursor to duller post-apocalyptic manga like Fist of the North Star) from Patrick Macias back in the day. Together, they make a double punch of apocalyptic 1970's chaos, with Devilman adding a sheen of respectability and noble tragedy by way of Milton's Paradise Lost.
Devilman in particular is a great read (it's available in a Kodansha Bilingual edition), although Go Nagai has real ups and downs... he's done lots of total garbage, and his earlier work is far better than his later work.
11. Evil God Legend (Jashin Densetsu)
Author and Artist: Kentaro Yano
Even though it's not particularly good, I feel like I should mention Kentaro Yano's H.P. Lovecraft manga, Jashin Densetsu ("Evil God Legend"), which came out in conjunction with the Japanese edition of the Call of Cthulhu role-playing game. This is a list of my favorite manga, not necessarily the best manga, right?
Yano does have some other credits doing romantic comedies and such. I should also mention Daijiro Moroboshi's Yokai Hunter, a bizarre horror/sci-fi manga influenced by Lovecraft and assorted Asian mythology. Moroboshi draws in a super-detailed, fine-line, yet cartoony style which vaguely reminds me of Hayao Miyazaki, another artist who narrowly escaped making it onto this list.