Quote (GoGoData @ Nov 18 2011 10:42pm)
History's strongest disciple kenichi manga is decent. A lot better than the anime.
Vagabond manga = the best in the world. 
Kekkaishi isn't very samurai, but I think it's decent so maybe check that out?
Definitely check out Vagabond if you haven't already. My sig/ava are from it if you need a quick idea what the character art looks like.
For more overall kinda stuff (not really martial arts specific or anything) Dohran, Muramasa, Kazan, Ushio to Tora if I can think of more I'll post here after.
I just noticed you don't have Hokuto no Ken (Fist of the North Star)..Old but classic martial arts manga with other spinoffs to keep you entertained (Souten no Ken)