The above are all interesting takes on two different shows.
Himura Kenshin is the main character in ni different show.
The show most people are familiar with is Rurouni Kenshin, translated literally as Kenshin the Wandering Swordsman. The story of Kenshin is as fascinating as it is historically informative. It takes place during the Meiji era of Japanese history, in the year 11. (1878 to us.) Kenshin was (as mentioned above) an assasin during the violent uprising which lead to the Meiji era. His skill and poise were instrumental in bringing the former government down. He became known as the Battosai, a title based on his skill at a certain sword style. The series Rurouni Kenshin surrounds the events which take place when Kenshin meets a young woman named Kamiya Kaoru in the streets of Tokyo. He, the young woman, the young thief Myojin Yahiko and the ex-mercenary Sagara Sanosuke form a kind of family unit, with Kenshin protecting the people of Tokyo from the likes of gangsters, and remnants of the violent Meiji revolution.
The show combines moments of Samurai action (The above mention of Ninja Scroll paling in comparison to this show is accurate, I think.) with a well thought out and well written plot. While the show does have its moments of levity, this series is more serious than shows like Ranma 1/2.
The other show starring Kenshin is the (also excellent) 4 part OAV series, Samurai X. I actually like Samurai X better, for reasons I mention in the node for that series.
There is some confusion about this, because Samurai X is the name of the OAV series, as well as a movie, in the Rurouni Kenshin timeframe.
For more information on Kenshin, check out http://oro.simplenet.com/oro/ .
It's slightly out of date (Kenshin is now available in the states, thanks to Media Blasters), but has in depth information on the show and characters.