Do receptacles require a 20 ampere breaker?
Answer based on the NEC in the US.

In some areas with local amendments to the NEC maybe, but it's not an across the board code requirement. 

There are areas in a home that do require 20A circuits, such as bathroom receptacles, laundry receptacle(s), kitchen/DR/pantry receptacles. Other areas such as garages, utility rooms and unfinished basements it is definitely a good idea.

Personally I do most receptacle circuits on 20A, but this is not a hard and fast rule for me.