I think the biggest misconception about Kayle is that she needs AP or AD to make it, really with Righteous Fury she already does a ton of damage per hit so all you really need is attack speed to make her awesome. Getting AD and AP late game will push you over the edge but in early game you just need to make her fast to own. She does not need a lot of health past level 6 because her ult can win you most 1v1 battles and keep you alive in team fights. Just remember if you are going to drop your ult on someone else to save them avoid fights where people can focus you down. Her ult is the key to winning any fight. With this build you can almost always kill a champ before her ult is down or very quickly there after.
I build AD, AP, and attack speed. This gives her a good mix all game and gives you a little boost scaling into late game.
All attack, Kalye is an offensive carry and since she has good sustain and great staying power with her ult then defensive masteries are a waste.
I max Righteous Fury as quickly as I can since that is her primary DPS skill. Healing is not as important for her so I max that last and focus on doing damage quickly.
You will never complete this build in a normal game generally I have 20 kills and the game is over before I can finish it. If you are in a game long enough to finish it then you are a GOD! I end up keeping the prospectors blade until I get the Vampiric Scepter and then use the money to build Hextech Gunblade. Remember to use the active on Sword of the Divine! That combined with the black cleaver, her passive and reckoning can shred through almost any tank no matter how much armor they have. I love seeing Jax expecting to dodge me when I use Sword of the Divine.
Pros / Cons
Insane DPS with righteous fury
Good from early game to late game
can take almost any other champ 1v1
Needs to have abilities up to fight
Could use more cool-down reduction early game
No mana regen (but doesn't come up much in Dom games)
A couple of good little tips
Always use Divine Blessing out the gate it will give you a quick burst of speed and the mana will be refunded before you leave the gate.
If you are going top hang back and fight like you are a ranged carry (because you are)
if you are going bot be aggressive, kayle can take most champs right out of the gate so don't be afraid to push.
Try and bait people with you ult wait till they come at you and then drop it to absorb damage
Surge and exhaust push Kayle into the realm of OP when they are used together. I love going bot and dropping both of these for a quick early kill. If you go top, stand in back and use Surge and righteous fury to pound them, if anyone gets close to you exhaust them to keep them back.