Welcome to AD Kennen build for Preseason 3 !
Updated after 1. balancing patch !

Pros:

* Highest base attack speed out of all ranged AD Carries (0.690)
* Highest bonus attack speed per level out of all ranged AD Carries (+3.4% per level)
* Highest base attack speed at level 18 (1.089)
* Very high base damage and low cooldowns of abilities
* Easy initiation with Lightning Rush
* Escaping opportunity by Lightning Rush
* Base defensive stats are above the average ranged AD carry.
* Good laning phase, with access to stun if you land a Thundering Shuriken
* Better early game than most AD carries, and a comparable late game.
* Kennen is very good farmer, easy last hits by Q, whole wave by E + W.
* 550 Auto Attack Range. It is better than: Urgot, Sivir, Teemo, Jayce, Graves, Kayle, Twisted Fate, Kog'Maw (without Bio-Arcane Barrage)
* And he has energy, he is not going out of mana.


Cons:

* You need to manage your energy resource. If you run out of energy unplanned before you finish combo, you´ll loose fight.
* 3/4 of his abilities benefits from AP. This is not AP Kennen. AP Kennen is very strong.
* Low respect from your teammates in Champion Selection

I don´t have much to say to masteries - you can read yourself what they are doing.

It is classic ADC bot masteries. I´ll say only that you shoud not change it much.

9 Points in Defense tree is giving you sustain: Improved Heal in Summoner's Resolve , Armor and Health.

Flash
Flash rule: I use flash because Kennen has no real escape other than Lightning Rush and you can't run through walls.

Heal
Heal: Personaly I like to run heal since he got buffed he is very strong on low levels.
Heal is more effective when you use it on yourself, not by support. And it increase health with improved Summoner's Resolve in Masteries.

For aggressive players is probably better Ignite
Extra DMG and reduction of healing. Cons are that Ignite have short range, and Heal is more effective.

Cleanse Another great deffensive spell is cleanse. It totally counter Ashe.


Bad but not fatal error would be Exhaust
Exhaust should be on your Support lane partner not on you.

Classic ADC bottom runes:

Marks: 9 Greater Mark of Armor Penetration

Seals: 9 Greater Seal of Armor in order to make it harder for the enemy AD carry to kill me.

Glyphs: 9 Greater Glyph of Scaling Magic Resist in order to defend against some of the magic damage I will face in team fights.

Quintessences: 3 Greater Quintessence of Attack Damage in order to reach some DMG on start.
You can also use Greater Quintessence of Armor Penetration

I level up my abilities in order R > W > E > Q.

Thundering Shuriken This is a skill shot that has no scaling with AD kennen, so use it as a stun tool and farming last hiting tool. With W and a E, you get a stun. You can use it as a free harass into your enemy or scouting brushes. Those facts are actualy reasons why I pick it on lvl 1.

Electrical Surge This is your main damage ability in lane, it's cooldown reduces drastically as you level it up, and the AD ratio on the mark of storm proc goes up as you level it, so level this ability first.

Lightning Rush This transform you into lighting ball. You run really fast. It can be used as an initiate, a counter-initiate or escaping tool.
The cooldown and damage get better as you level it, so level this up second.

Slicing Maelstrom Ultimate ability can do up to 240/435/630 damage, and stun a target for 1 second, I level this up as soon as possible.
Keep in mind, this ability can only strike the same target every 1/.8/.66 seconds, double that which is stated in the tooltip.

Starting Items
Pick Boots and potions or Doran's Blade

Rush items
You need to buy those items as soon it is possible.
Berserker's Greaves Doran's Blade and Zeal => Phantom Dancer

Core
After Phantom Dancer rush Infinity Edge
This combo is reason of the most ADC pentakills / rest is Ezr, Corki Trinity Force+ Infinity Edge :)

After that build Bloodthirster or Last Whisper depends on enemy armor stats.

Category Late game survivality
You should pick your favourite item.
If enemy team has heavy AP or good CC combo pick QSS for ,,cleanse,, => Mercurial Scimitar because late game fights are about position, synergy and burst DMG to carries.
But if you are against AD Jugernauts like Tryndamere Garen you must build Guardian Angel

Situational items
Black Cleaver only if you think that you don´t need lifesteal but more armor penetration.
Runaan's Hurricane you´ll get crazy attack speed witch means more stuns by W passive marks.

People Kennen lanes well against.

Ashe Kennen has better stats and 4 DMG skills instead of 2. Her close range ult has lower stun time.
Ezreal Dodge his skills, and he can't do much against you.
Kog'Maw He has to spend mana to match your range and dmg, you should be able to trade him as long as you can land a Q on him. You can run away by E from his slow and ults.
Miss Fortune If she trys to trade with you, she will run out of mana.
Sivir Avoid her boomerang and you´ll be fine. Her damage is lower than yours.
Vayne Your Escape is better, your CC is better, your damage is comparable, and your ultimate will always hit her even in stealth.



People Kennen doesn't lane well against.

Caitlyn isn't a counter for Kennen, but Cait's job is easier. She has greater range too.
Corki His Gatling Gun is very strong in duels, and his Valkyrie allows him to escape from any gank or bad moves. You should farm passively against him. Your support can make some good moves than trade with him and try to punish.
Draven Early strong, his Q can burst you a lot.
Graves Really tanky because of true grit, but you can passive farm against him and be better late.
Tristana She is good early game against you, you'll have to really abuse her mid game in order to beat her.



Good Partners.

Sona Really good kill pressure at 6. Good aura benefits.
Janna Her shield is really strong on kennen.
Lulu Lulu brings damage, cc, shield and AP. She is missing only heal.
Soraka She can really punish casters like Graves with silence, and can be fairly aggressive. She is a good lane for passively farming because she has heal.
Leona Awesome cc and great initiation.
Blitzcrank Annoying and dangerous CC. He can do tons of damage to stationary targets.
Alistar OP Sup with a lot of CC. And heal.
Taric Almost Same like Alistar.

I would pick AD Kennen if I saw the enemy bottom lane has low sustain, or you want a bit of CC on your AD carry.

Very funny and effective alternative.

Strong DMGer with best CC possibilities from all ADC.


Please do leave me a comment and vote the guide, it means alot. If you downvote, please do tell me why, and what should be improved.
Thank you for your time of reading my Guide. Good luck and have fun ...

9/12/2012: Guide published!
11/12/2012: Few description changes
14/12/2012: Black Creaver removed from the core after nerfing in 1. Balancing patch - This change leaded to big changes of the whole Core Build. Also added some Items descriptions.