It is certainly worth reading Shakespeare's plays and his sonnets. I have read them all, though would love to read them again. I haven't read his other poems, besides the sonnets, though. If you have read many of his plays, I would encourage you to read a selection of the other Elizabethan and Jacobean playwrights - Jonson, obviously, but also Marlowe, Webster, Fletcher and Beaumont, Massinger. This was truly one of the most remarkable periods in English literature. It shows you how great Shakespeare was, that he stands out in a time of many brilliant playwrights.