I highly recommend Emanuel's. (don't forget to know key developments since the last printing, like Trinko and Empagran)
The Hovenkamp treatise is helpful; it should be in your library (Hovenkamp also writes the Black Letter Series outline, but I found Emanuel's more useful than Black Letter).
Case law is very important to this class; the Sherman and Clayton Acts aren't very detailed, so judicial development of the law is crucial. I found keeping up to date on recent case law incredibly beneficial for learning the law and doing well on the exam.