Well, I thought it would be nice to get all of those in a single forum thread.
So state here your strongest roles, your playstyle in that role and your champion pool for it. By champion pool I mean champions that you are actually confident with and that you have good results with and experience.
I will start:

-Mid:
My prefered role at the moment and the one I have been excelling most in Season three. I normally prefer running utility mages mid, but I also have a taste for heavily roaming AP mid champions and hyper-carries. I usually don't play assassins mid, with some exceptions. Some of the mids I play excel in a poke comp.


Utility mids champion pool: Ori, Gragas, Anivia, Morgana, Zilean (Used in case a protection comp is needed).

Roamers: Twisted Fate, Eve.

Hyper-carries: Karthus, Ryze, AP Kog

Assassins: Diana

-Top:
My lane through the whole of season two and one that is still one of my strenghts and that I know how to play. I normally opt for AP kitting tops and try to transform an early advantage into lane dominance. I tend to be a good duelist at top lane knowing when to trade and maximize the damage my opponent will take through minion hits and when not to trade. Even though some of the top champions I will list can go mid too, I am stating the champions where I like to run then.

AP tops: Rumble, Vladmir, Elise, Singed, Gragas
Bruisers: Jax, Irelia, Olaf, Yorick, Wukong


-ADC:
I have recently been playing AD carry quite often and with some very good results. My ADC champion pool consists of either champions that aim to have a heavy pressure in lane right from the start or hyper-carries.

Lane dominant AD Carries: Draven, Sivir, Graves
Hyper-Carries: Tristana, Kog
(I also have a big experience with Corki, but unfortunatly he is not a very competitive pick at the moment with his core item nerfed to the ground and the changes in penetration not benefitting him much).

I have been playing mid since I have played league. I like to play mids that I can farm safe with, right now having alot of fun with twisted fate. I also play ahri now and then. I'm level 28, should be 30 by the end of the week

i have been playing jungle consistently for the last couple weeks and have learned more and more when playing with randoms and others on bbf. i usually play early gank champions but i am not limited to other late game champs

my champion pool right now would be
eve, udyer, nunu, skarner and elise. the only champs i dont own for jungle are jarvan and shyv so i have a vast selection for other jungle champions.

Just wanted to list my usuals

Top: Shyvana, Poppy, Renekton, Mordekaiser, and Lulu

Jungle: Shyvana, Poppy, Jarvan IV, Maokai, Cho'gath

Mid: Mordekaiser, Veigar, Ziggs, Gragas, Cassiopeia, Orianna(still learning her)

Support: Taric(fabulous), Leona(FOR THE SUN), And Lulu, Maokai(if I am feeling crazy)

Adc: I aint got much besides Corki, saving up to grab graves soon.

most of my champs are probably late game carry potential, some mid potential if ahead, but usually kinda meh in early game(except the supports).I focus on farm usually in most cases and stick to my lane and push or poke the enemy.

TOP: Darius Garen Kayle Teemo Lee Sin Nunu Poppy Shen Singed Tryndamere Warwick

JUNGLE: Darius LeeSin Master Yi Nunu Shen Tryndamere Warwick

MID: Akali Annie Kayle Lee Sin Master Yi Morgana Ryze Teemo Twisted Fate

ADC: Ashe Ezreal Kog' Maw Sivir

SUPPORT: Alistar Garen Kayle Nunu Shen Soraka Thresh

I could use some better ADC and more... well... a better Champion pool... :I

It's far bigger than my champ pool haha!
I got 29 last night so hopefully ill be 30 by Friday! I'm pretty sure my focus will be on playing mid in ranked games but when I get 30 I'm going to practice a lot more before getting put into bronze V xD

lol aim higher bud!

I want to get in gold somewhere but I don't know anyone who plays in that division who can help me out, my friends play in silver V and II so I can only learn so much from them.

[font=arial:3dv3ar3t][size=2:3dv3ar3t]My preferred role is Mid, and can play pretty much any style of mid to go with any type of team compostiton. I don't have a certain preference to mid style, I will play whatever we need for our team comp.
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Mid champions I am extremely confident with(Bolded are my very best 3): Ahri, Annie, Diana, Evelynn, Fizz, Karthus, Katarina, Kennen, Lux, Morgana, Oriana, Ryze, Twisted Fate , Akali, Anivia, any AD assassins.

Mid champions I have enough experience with I could play them: Ziggs, Zyra, Vlad, Nidalee, Gragas, Kassadin, Brand, Morgana, Xerath.

Champions in mid I can't play well: Fiddlesticks, Karma, Heim, Syndra, Veigar, Viktor.
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So as you can see my Mid champion pool is very large. Some of my mid strengths are: farming (all champs), roaming (with certain champs), WINNING LANES AW YEAH.

My second role I prefer is ADC, and I can literally play ANY traditional ADC with enough confidence and skill to do well.

[/size][/font:3dv3ar3t][align=center:3dv3ar3t][font=arial:3dv3ar3t][size=2:3dv3ar3t]Preffered AD carrys: Ashe, Cait, Draven, Ezreal, Kog'Maw, Miss Fortune, Tristana, Varus, Vayne
But I can also play: Corki, Graves, Quinn, Twitch with much success, just don't like them as much.

the one ADC I don't play: Sivir.

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[font=arial:3dv3ar3t][size=2:3dv3ar3t]I am a very strong farmer when playing ADC, and I also position well in team fights 95% of the time!
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So last night I decided to try jungle. I was on a loosing streak mid (3 games lost within an hour) and I was playing terrible!

I went to good old google and looked up some basic jungle to do's and not to do. With this information in my mid I played 4 games. 1 with a nunu as I thought it would be simpler to play him first. He isn't the kind of champ I would and that was clear after my performance with him!

I then decided to try jarvan. I played 3 games with him and they were all wins! I think I did pretty good with him for first time playing and I will be playing him again later today.

I also purchased some other champs like Elise, amumu and cho so I have some other champs I can jungle with.

If I enjoy them all it will probably mean ill switching from mid to jungle!

I'm still yet to try play support properly aswell but I think ill leave that for the future!