A little explanation.
Probably 90% of the people reading this guide are wondering wtf, why grab these items when GP is so strong with Crit? Welp bro, that's because this is 3 v 3, which is completely different then 5 v 5. This build costs about 12k fully bought, while a typical offtank (
Warmog's Armor/
Atma's Impaler/
Trinity Force/
Force of Nature/
Infinity Edge) costs about 17k. This is pretty well impossible to get on 3 v 3, even if fed. Therefore I use a build that is strong at all stages of the game and counters your enemy quite nicely.
You might even say this counters the metagame in 3 v 3, which is full of bruisers and high damage assassins.
Gangplank can deal with these quite easily.
For example, GP shuts down Jax completely. With proper runes, GP eats Jax alive at all stages of the game.
However I did include a crit build that works well in 3 v 3 just in case you were wondering, or whether you didn't need to worry about offtanks that much. Note, sell Philo stone in order to buy Triforce :I
Skill Order
Y I NO MAX E?
Cuz heals OP BRAH.
Parrrley is such a good farming tool it's ridiculous.
If you want to, farm all day and 1 v 3.
If you don't, that's k too, Parrrley and you STILL have more gold then the enemy.
Go do the dishes, come back, Parrrley STILL have more gold.
Go to work for 8 hours, come back Parrrley STILL have more gold.
That's why I take Parrrley first and max it pretty fast.
But Heals are just so good. Once you get your 
Spirit Visage you'll heal for about 420.
What does that let you do? Stay in lane FOREVER. You want to farm IP? Go 1 v 3 all day, defend towers and heal up, lulz. Nah I'm just trolling you. But heal is still super good.
We level E last because all it gives is AD and MS and are main damage doesn't come from that. We don't NEED the MS as much because we have our passive, we spec into the Utility tree so far, and we also get a Shureyla's Reverie. Even for dps plank I would spec up Q first, and then maybe E if i'm having a super easy lane. Yes E will increase your overall damage, but Q is much better for farming, and W is more necessary for ganks.
*Not sure if
Perseverance
affects healing anymore (it did in first season).
GP's Booty
Yarr, what treasure did we get from the high seas this time, eh?
Well yarrr, we got ourselves tons of booty me mate's, yarrrrr, i got meself a nice 
Boots of Speed to start off with, then some 
Health Potion. On my first base I get a Madred's Razor and 
Philosopher's Stone (and if I have enough money I finish boots).
From there you should know what to buy :D
(HINT: It's all in the cheatsheet, first one crit, second 1 vs heavy magic damage, 3rd one vs heavy ad, last one general)
Jungling?
I don't recommend it. Gangplank is a great jungler in 5 v 5, but I feel he doesn't have good enough ganks and is to mana hungry for 3 v 3 jungling. :/
I'm not even entirely sure if it is possible to jungle with Gangplank in 3 v 3 :O
Optionus Prime
Everybody likes Optionus Prime.
So I figured I'd put down some Options for you too, and maybe you can be Optionus Prime :D
Primarily this deals with:
Sword of the Divine
Actually a pretty good item for GP. I wouldn't recommend it unless they have 
Jax though, and even then I don't think it should be make or break.
You should own a Jax super super hard early game anyways :D
Another option is 
Malady. I don't much like it though. It's OK, but 
Wit's End + 
Madred's Bloodrazor is just so much better. If they have zero damage though, it + Madred's Bloodrazor is pretty deadly.
We've already been down the road of why we don't have crit, so I hope you aren't going to expect me to list any of those items. :P
However I will admit that if you want to get an early 
Zeal and turn your Shureyla's Reverie into a Trinity Force, that is OK. I would pretty well never do it though.
And I SUPPOSE if you REALLY REALLY want to, getting a 
Soul Shroud instead of Shureyla's Reverie is ok. It's really only useful for the hp though. :/
Oh and speaking of health, Warmog's Armor is only an ok item on TT, which is why I don't get it.
IF you feel you can farm it well enough early (talking like 15-20 min here) then it would an ok buy, I suppose. You WILL gimp your damage by doing that though.
Closing
Yeah so I hope you guiz like my way of playing Gangplank. I'll be continuously updating it and making changes so it will look much better then release. :D
Please leave a comment below if you think something could be better. :/
Update Log:
Released Nov. 16th 2011
Updated Runes Nov. 16th (ty Searz)
Updated masteries and added a build Jan 11th
Build Guide
Discussion (89)
Ashe.
Veigar.
Awareness
is super strong on 
Durability
and
Veteran's Scars
are strong as well.
