Hi! I made this guide to notify whoever is not aware of this setup and explain why it's good and should be considered.

This is the current meta in EU. It has been used in Dreamhack and has won in most cases. It's really balanced and works well, will win you games if you play correctly.

Enjoy!

A Jungler
An Off-Tank Solo Top
An AP Carry Mid
A Support Bot
An AD Carry Bot

Pros:
- Having a Jungler means an extra solo lane > more exp and gold for the team and allows for early ganks.
- Having an Off-Tank farm alone means they can build tanky whilst doing good damage in team fights.
- Having a Support bot with your AD Carry gives your Carry more sustainability in lane and more gold to farm up.
- In this setup the Jungler is required to go off-tank. This is a pro in itself as you have more off-tanks to soak up dmg.

Cons:
- There is no full tank in this setup, so if the off-tank(s) don't farm well and are not tanky enough to soak damage then the team fights will be trickier.
- Having a support means your team deals less damage in team fights, but this can be compensated by their heals, cc and potential ganks that were avoided by wards, or certain ganks successful because of wards.

Pure tanks aren't as useful as Off-Tanks just because they lack damage. Damage is important and off-tanks should do comparable damage to the carries. A good example is Alistar, he can mainly go pure AP items because of his Ultimate which allows him to soak up a lot of damage. Or Irelia who can deal True Damage and CC stun slow enemy champions whilst being item tanky (due to epic farm from her Q).

The Jungler: Must be able to gank at lower levels (mainly mid and bot) and should have CC as early as level 2 (in ideal cases). Their other roles include donating buffs and CC'ing in team fights whilst being very tanky (Tankier than the Off-Tank in some cases). This means you won't be a full time jungler and will have to deal without having buffs later on in the game.

The Off-Tank: Should be very sustainable in lane. You will rarely leave lane unless for a Teleport gank at bot. You won't see a lot of action and it's usually better to be less aggressive and just farm. You're really item dependant so make sure you last hit well.

The AP Mid: Should be able to play rather aggressively attempting to harass whenever possible. You should prepare for ganks and will get the most action at the start. AP mid usually gets donated the Blue Buff from the Jungler. Must always be on your toes ready to flash away at a sign of a gank or bait for a gank.

The Support: Must ward certain places. They can also setup ganks with wards by placing them in the brush and having the Off-Tank solo top teleport down. Must not take any last-hits from the AD Carry, must heal the AD Carry or CC the enemy. Should be able to coordinate ganks with the Jungler. Later in the game should have an Oracle and start to clear wards at baron and dragon.

The AD Carry: Should farm heavily. You shouldn't be playing that aggressively unless you know you can. It's usually a farm race between the opposing AD Carry. AD Carry gets donated the Red Buff by the Jungler.

Jungler: Should start out with either Cloth + 5 Pots or Regrowth Pendant + 1 Pot. This varies between Junglers but ideally you want the Gold Per 5 Items ASAP. Philosophers Stone + Heart of Gold should be staple items in your build as you will not be in your jungle 24/7 and will have less minion kills. But do try to keep up whenever you can.

Off-Tank: For an Off-tank with self-sustainability they should aim for a Doran's item early. If not, they should get Boots + 3 Pots (or cloth + 5 pots) to stay in the lane as long as they can.

AP Mid: It's almost always Boots + 3 Pots for the early game harassing and aggressiveness unless you have a heal/drain then you get a Doran's Item.

Support: Should be starting out with a Faerie Charm + 3 Wards + 2 Pots. This allows for early warding and healing up to save mana or if you're a support champion that has no heals at the start (Janna). They should also rush the Gold per 5 items ASAP such as Heart of Gold + Philosophers Stone 9staple items similar to the jungler). Later on you should get an Oracle if the other team has a Support to clear their wards.

AD Carry: Should start with a Doran's item for early damage and health to survive being ganked and do more damage for ganks. They should farm up for the expensive items that make them AD Carrys such as Trinity or Infinity Edge.

Almost every Champion should have Flash with a few exceptions. But here are the main Summoner Spells for each roll.

Jungler: Should have Smite. No exceptions. This has been mentioned many times, you need Smite for counter-jungling, to speed up jungling and to steal buffs.

Off-Tank: Should have Teleport. Only exception is Shen for obvious reasons. Teleport is such an underated Summoner Spell. It helps setup ganks, or if you're mid attempting a gank or helping out and suddenly their Top starts pushing you can teleport back to your lane. It has many uses and you are usually the furthest away from the action.

AP Mid: Should get Ignite to secure kills and counter certain heal champions and prevent supports from healing a dying enemy champion. Also very good for early ganks.

Support: Should get Clairvoyance. It can prevent ganks, help setup ganks, find the enemy jungler, check if the enemies are at baron/dragon. Such a useful summoner spell on such a low CD.

AD Carry: Should get exhaust or ghost for more chase / survivability. Disables the other team's AD Carry (which you will be paired with at bot) and slows an enemy champion for some early ganks. Can help save your support if she's getting bullied by the enemy champion. It fits best on an AD Carry as he has the most DPS and this allows you to hit that certain champion for longer.

There may be some mistakes and wrong assumptions, you may correct me if anything is out of place.

My first guide so let me know what you think. Thanks for reading!