Augustine and Aquinas : Differences in Theology?

First time on these boards, please forgive me if i've put this thread in the wrong area.

I'm a complete and total layman whose encounters with theology tend to be restricted to either as part of the history of ideas or as part of the history of philosophy.

I wanted to start a discussion namely with an important question, namely the one above. Both St. Augustine and St. Thomas Aquinas' loom large over the intellectual history and theology of the church.

Not having the mental fortitude nor the monetary assets to purchase the 64 volume version of the Summa Theologica and only possesing copies of Augustine's Confessions and the City of God, i'm ill equipped to address the question.

What are the differences in theological outlook between the two, besides the marks of Neoplatonism and Aristotle's philosophies on their modes of thought?