I usually find my team destroying the other team with Fiora as a slightly tanky carry. Alistar as the obvious tank, and for his CC. And lastly, Master Yi for his obscene attack speed boost with his R and the ability to chase the opponents that try an escape. Alternatively I find that replacing Master Yi with an AD carry with CC, like ashe, or an AP carry with CC, like Lux and hopefully soon to be Zyra, works wonders and if played right can dominate almost any opponents. Of course you could also replace Fiora for someone like Darius and Alistar for most other tanks but with darius I don't find you'd get the damage output as you would with Fiora.
TL;DR: Alistar, Fiora, and Master Yi/Ashe (only if played right)