Rage of Ken!
In Defense of Ken
Ken's Street Fighter Battleground!
Violent Ken

Name: Kenneth Masters
Birthday: Feburary 14, 1965 (that's right! Valentines day!)
Name meaning: Ken means different things depending on how it is used.  I've heard that it means "inner spirit", but the best way to describe Ken is "an attack using the upper body".  For example, the Hadouken is translated as "motion wave strike.  Shoryuken is translated as "rising dragon punch or rising dragon fist."  So Ken basically means "fist, strike, punch, or attack", depending on how it's used.
First appearance: SF1 (2P)
Ken was the son of a wealthy family.  Anything Ken desired was brought to him with little effort.  However, Ken was also a spoiled little brat.  Ken also tended to be rude, obnoxious, and lacked any discipline.  Finally, his father put a stop to this and decided to give Ken some self control.  Ken's father sent Ken to Japan, where young Ken would study with an old friend of his.  A Shotokan teacher named Gouken.  Once Ken arrived in Japan, he met Gouken's other student, a quiet Japanese boy named Ryu.  Ken and Ryu soon became the best of friends, but at the same time, rivals.  The way that expressed their Shotokan art was different as well.  While Ryu went for tradition, Ken decided to "improvise" a bit.  It was through some of this improvisations that Ken was able to master the Shoryuken even more then Ryu.
Eventually the first SF tournament came.  Both Ken and Ryu entered, but it was Ryu managed to advance to the finals and defeat Sagat.  After the tournament was over, the Shoto friends went back to Japan to tell Gouken of their adventure.  Unfortunately, Gouken had been killed by his brother Gouki (Akuma).  After this incident, Ryu stayed in Japan while Ken went back to the states.  Ken eventually met Eliza, the sister of Jane (who happens to be Guile's wife) and married her.  Ken had a kid named Mel as well as several other adventures.  Currently, Ken is teaching his son Mel and fellow SF Sean the ways of Shotokan karate.  Ken is also still training himself, trying to prove to Ryu who the better fighter is...
The legacy of Ken
This mini section will go through a timeline of Ken's adventures in the SF games, as well as offering trivia information and interesting facts.  There is also a section like this dedicated to Ryu at the RS shrine.  Go there for info on him.
We meet Ken and his Japanese buddy Ryu for the very first time.
Interesting fact: The hadouken was yellow in SF1!  That's right!
Side note: The hurricane kick looked very different back in 1987 as opposed to today.  Ken would jump up into the air first, and then spin like a helicopter.  It was almost humorous to look at.
Ken looked pretty much like he did in Street Fighter Alpha, only Ken's hair wasn't as long and he didn't have his hair tied in a red headband.
Ken and Ryu return along with Balrog and Sagat.  New characters are also added.
Interesting fact: Until Super Street Fighter 2 was released, Ken and Ryu had the same voice actor!
SF2 Champion Edition
Ken gets the legendary 2-hit shoryuken that could mess an opponent up real bad!
SF2 turbo
Nothing new, except that Ken can now do the hurricane kick in midair
Super street fighter 2
Ken gets the flame Shoryuken and the midair hurricane kick is slightly altered.
Side note: Ken finally gets a different voice actor!  While the original voice actor stays as Ryu (and also does a little bit of Dhalsim), Ken got a different voice.  A lot of people hated it though.  Some people said it almost sounded nerdy.  It wasn't as bad as Guile's though.
Super Street Fighter 2 Turbo
Ken gets the Shoryuu-Reppa super move as well as an assortment of new kicks.
Street Fighter Alpha
In terms of attacks, Ken gets a ground roll and the Shoryu-reppa.  In terms of looks, Ken looks just like he did in the 1st SF only that Ken's hair is about as long as Terry Bogards and is tied up with a red bandanna that would eventually become the trademark item of his best friend Ryu.
Street Fighter Alpha 2
Ken gains a ground roll where he rolls flat on his back.
Interesting fact: It is in Ken's ending that we see him give Ryu the red headband that would end up becoming Ryu's trademark item.  This ending was possibly inspired by SF2: The animated movie.
Street Fighter 3
Ken gets an admirer.  Sean wants Ken to teach him badly.  Ken refuses at first, but later changes his mind.  Ken also gets a new super: the ShippuJinraikyaku
Side note: Originally, Ken and Ryu weren't supposed to be in SF3!  But thousands of fans couldn't allow that to happen, so Capcom went back to the drawing board and added them back in!
Street Fighter Alpha 3
Ryu already had a schoolgirl after him, now it was Ken's turn.  Enter Karin Kanzuki, who is very similar to Ken.  Karin also came from a rich family, was blond, and was used to getting her own way.  Ken also gets a couple of moves from his past games brought over.
The crossover games
Ken was just really good!  His hurricane kick actually lifted Ken way into the air, and his shinryuken left a portal of flames around his body!
Ken's Super's:
Shoryu Reppa-A series of shoryuken's ending with a flaming punch
Shippu Jinraikyaku-A series of kicks followed by a very powerful hurricane kick
Shinryuken-A dragon punch that goes in a spiral...if you press any kick button rapidly (or rotate the d-pad) the super will do more hits..