I was playing normal draft just now and someone from the opposite team picked akali. I've been wondering about a counter to akali to keep her from farming AND to keep her from killing her opponent in lane.
Ladies and Gentlemen, I present you:
Udyr with the correct runes and masteries (and maybe even without) counters akali ezpz.
Plus he is not expensive, not really hard to master and quite a strong farmer / toplaner too. When she comes to attack you, stun her with Bear(E). Then hit her once with Tiger(Q), for some nice burst. When you become damaged, leech HP with Turtle(W). As easy as that. Also, at like level 1-5, she will try to harass you with just her Q and then walking up to you and hitting you with a base attack, proccing the Q. To counter this, simply use Turtle to take away some of her damage and then just proceed with using Bear + Tiger.
Buy Wriggles first item, for even more sustain, second buy spirit visage, nice cd reduction and MORE sustain + MR, and then I like to either finish mercs or instabuy Wit's End.
Also, if akali starts using her alwaysannoying shroud, pick up an oracle's elixir. Now she can't even come close to you without being stunned and Q'd.
I hope this will help you, I'm sure there are some more counters to her, for example rumble, maybe GP too, but this "guide" is about Udyr. If you have any questions, comment and I'll try to answer them. Other replies will be appreciated too.
PLEASE NOTE: I am just trying to help the community here and stop the forum from flooding with akali QQ threads, this is NOT a rant against the people who think akali is OP.