Hey,
Just wanted to add that if Corki goes all in with Valkyrie, I'd say there's a 90% chance there is a gank very close, unless he's absolutely sure he can kill you, without dying himself.
Why would he waist a summoner like flash for some harass? ;)

As an ADC it's not your job to take their ADC down, it's your job to take down which ever target is closet, if you go in for their adc you will most likely be dead before you even get in range. Their adc is a job for an assassin like Zed, Kha'Zix or Talon or some1 like Jax, Wukong or Olaf.

Other than this, excellent guide, read it all through, some of it several times.
+1.

I'm not a fan of this guide.
Havoc increases damage by 3%, this is A LOT. You're playing marksman, your job is to do as much DPS as possible. The defensive tree is much stronger S4 and I feel that jugganaut is a much better use of mastery points than mana regen and some lifesteal. Speaking of lifesteal, you have 3 LS quints. Vayne is a very bad wave-clearer early and should you get pushed to tower you will miss a lot of creeps due to the fact that your damage isn't high enough to last hit under tower.

You finish LW too late. This is season 4, the supports have MUCH more gold, that leona is going to be stacking a lot more armor. Not only that , in teamfights you're going to be spending the vast majority of your time kiting the enemy top-laner and jungler who are, generally, armor stacking champions such as shyvana, mundo, renekton, olaf etc.

Using bloodthirster to replace a defensive item will not work against A LOT of team comps. What are you going to do when you get Lissandra ulted, and then leona stunlocked to death. With no GA, QSS or Banshees veil you can easily get stunlocked to death and won't be able to put the extra lifesteal from bloodthirster to work.

This guide is, however, very well coded and of great detail, and to that I give you merit.

I love your guide!
I got my first penta thanks to this :)

Penta

hi I want to warn that you have made a mistake on Playing against kog maw'. You said '' Living Artillery does more damage for each consecutive one''. Actually that's wrong the damage still the same. The only differences is that when you hit a CHAMPION you do more damage than minions and monsters, and each consecutive cast cons MORE MANA.
hope that you correct it :)
ps: sorry for my bad english

@Magicslime - Thanks again! I actually use Barrier a lot more often now, but I still feel that Cleanse is still a good choice against most teams. It's just that I don't usually like building Quicksilver Sash unless they have some sort of CC against me on 3~5 people.

Well it's not another review, it's just one thing - the first build against low or no cc...
Why take cleanse if there's no cc? Barrier would be a better choice.

@Magicslime
Thanks for writing so much for me to fix. I took pretty much everything you said and fixed my guide. I was too lazy to fix it before, but now that I have time, I can actually make some quick changes. Review my guide again when you get the chance! :)

I liked your guide (though I haven't had a chance to play it yet), but here are some things I have a problem with:
The quick builds don't line up with the text builds, in the text the masteries are 21/0/9 but in the quick guide it is 21/9/0 (and you put a point into both defense and offense summoner spell masteries even though you only would take one at any point)
The quick builds aren't labled or differentiated at any point, I don't understand what the difference between the first three builds are and when I should use each. (I also dislike the condemn leveling first in some of the builds, but that's not really that important here)
The team fighting section isn't completely right... yes, you are correct in saying that you should target adc first, etc. But the most helpful advice really is attack the closest target. Only if a high priority target is in range should they be targeted. Thus the advice of never targeting the tank is not helpful because you should be targeting the tank if you can't reach the back line. Remember that if you die, you are dealing zero damage and helping your team 0%.
Finally, the in text item builds are not the greatest - building a stattik shiv is better than building two phantom dancers, if you must have that extra attack speed. The quicksilver sash in the balanced build can be upgraded to a mercurial as well (i believe this has been mentioned already)

Other than these errors, I thought the guide was well done and showed the effort you must have put into it. Nice job.

@anthonythe13 - Yes, it is. I actually forgot to put that up after Season 3 changes. I'll fix it now. Thanks!

the guide was pretty good but isnt it smarter to upgrade quickislver slash to mercurial scimitar?

Yeah, depending on your support and jungle, a stun support with a Draven can be a lot scarier for Vayne, and there's pretty much nothing you can do about it, unless your other lanes roam and help bot.