I would recommend:
Summa Theologica (for the educated theists)
Summa Contra Gentiles (for the uneducated theists and atheists)
Collective works of Aristotle (for everyone!)
Summa Theologica (for the educated theists)
Summa Contra Gentiles (for the uneducated theists and atheists)
Collective works of Aristotle (for everyone!)