Well, I've always enjoyed Nishimori Hiroyuki's sense of humour that can be found in his more famous work, Cheeky Angel. However, rather than the complicated plot in Cheeky Angel, Doushirou de Gozaru's story is much easier to understand; a boy, raised in Nevada to become a "samurai", has just returned to Japan, and he definitely has no idea that Japan is not all that he thinks it is.
Doushirou is this boy, now grown up and entering high school; accompanied with his tono (master), Kensuke, unenthusiastic Erika, and the newly-reformed delinquent Maejima/Saotome (take your pick), his story is full of great humour (which sadly, mostly works in written form) and epic story arcs starting from high school delinquents to facing off with yakuza.
Kensuke only adds on to the humour, with ways of thinking that usually defy the typical samurai master; in fact, he's rather the opposite of it, but whatever he's thinking always end up making me crack up with laughter.
But the best part is just how well Doushirou's Magic, as Kensuke refers to it, works, seeing how he changes everyone around him (mostly ex-delinquents) so drastically by the ways of samurai.
Overall, it's a great read, and though some might not be fond of the art style, I think it's a great improvement from Cheeky Angel. This series had so much potential though, and it's such a pity that it abruptly ended by the eighth volume.