Takehiko Inoue, mangaka of Slam Dunk and Vagabond. I really enjoy his work, as he does has very clean approach to motion. It makes all of his action sequences very translatable into a single fluid scene.

Ookubo Atsushi - His art style comes across distinctly in Soul Eater, but most notably (for a nerd like me) are his references to Lovecraft and various other literature scattered here and there.

Tanabe Yellow - A mangaka that actually makes shounen battles never feel dull. She does a great job balancing and weaving together different plots and backstories. Every Arc of Kekkashi is introducing something new.