WHAT?!?!?! No Mundo love? Its not like he has the most spammable annoying harass in the entire game. I have a friend who runs Swain and as soon as a cleaver hits, my friend throws down the snare. Since the enemy is slowed anyways they can't dodge the snare short of flash. Oh and at level 2, most people who are rooted do not last long against Mundo's free BF sword. And come level 6? Pshh they heal so much you can't come anywhere killing them. Only thing is both characters have a learning curve; Mundo has to get good enough to hit even intelligent enemies with cleaver and Swain has to not be one of the 1239480397543957420957394757032192309538209481 fail Swains out there (Not bashing all Swains, just most people cant play him for ****. I'll admit I am a total fail as Swain). Master that combo and you pretty much win.

well i must say taric yi or yi and anyone with hold. reason is yi gets double strike up and is maxing that first with his alpha strike. you stun or hold then yi alpha strikes and double strikes if you land the combo twice there dead almoste every time. plus fast pushing. taric goes support with clarity n giving good boost with heal.

on the side not most fun duo combo was morgan or lux with ryze mid. duo mid both have massive disables leaves mid crippled really frekin funny for other mid to be like wtf 2 are u serious, especialy if u have good 2v1er on ur team. and if everything goes perfect they will have to gank mid which with ur amount of disables is hard or they put a 2nd person mid which takes away from there experience and now there carry has babysitter leeching xp/gold/last hits. really entertaining. well gl and hf

at this point, after looking at all those posts, I think xin and pantheon would be best. if one person was caught off guard, pantheon can easily land a stun which would result in that combo by xin. by the time the enemy is airborn, pantheon would have already HSS'd.that combo is just full of damage and cc. Any other laning combinations?

shen and akali = OP

No one has mentioned this one, most likely because its not an ideal early game for either champion, but I've recently encountered it several times:
Nunu+Vlad
Their ranged harass and ability to heal/negate any opposing harassment is extremely annoying to play against.

For early tower downing:
Nasus+Heimer

For exp deny/strong harassment:
Cait+Janna

ive been vs sion taric in a 3v3. it was not fun at all. we won anyway because I was jax and could sit under a tower while trynd pwnt it.

Maybe not the best, but my friend and I do Nunu/Tristana a lot to great effect. Generally speaking, we'll have them fighting at their tower within a couple of waves, and when we both hit level 6, they die pretty quick.

Yesterday, end game, we went 4v2 and killed them all without going below half ourselves, and killed the 5th immediately afterwards

I've had success with TF and Shen, but also Trundle and Garen. The first 2 have a double stun/double teleport = GANK the other side of the map, then teleport back to your side of the map. As for Garen and Trundle, massive slow and impeded movement, while Garen silence's and spins + negative AR and MR = You die now. Slow to get going, then the death rains down.

A couple of extremely efficient combos I have run into.

blitz and Viegar,...Blitz does his grab, dmg combo and viegar does his stun, nuke= dead opponent.
(stick together all game)
Ryze and Zillian Either zil can slow then ryze gets his easy stun or ryze can just stun...Ryze uses everything zill double bombs= dead opponent.

These two combos I found very effective early/ mid and late game.

Alistair Ryze
Ryze Pantheon
Alistair Pantheon

Jungle Rammus, Fiddle sticks.

3 sec fear, 3 sec taunt in your face. 2 AoE ults.