Answer:
This is a common question on the GMAT, a test to gain admittance into business school.
Like is used to describe something that resembles something else. He runs like a rabbit.
Such as is used in situations where the object of comparison is certain. At the zoo I saw animals such as lions and elephants.
Take the last example:
1) At the zoo I saw animals such as lions and elephants.
2) At the zoo I saw animals like lions and elephants.
The first means that I in fact saw lions and elephants whereas the second implies that I saw animals similar to lions and elephants. Maybe tigers and rhinos.