At this moment, "The Group" (as they call the study) is going through the book of Romans one chapter per week. I get the pleasure of teaching multiple times, so I took it upon myself to do a personal study through Romans. Since the letter is theologically packed with truth and fulfillment based on the words and works of Christ, I decided to get two commentaries to assist me. I was encouraged at CBU by my professors to never buy sets of commentaries, but rather buy a set of different commentary books on whatever I am teaching. This way, you build a healthy library and your money it put into your current studies instead of spread out very abroad (even though there is nothing wrong with buying a commentary set!). I have done this and have found it extremely fruitful, resourceful, and wise.
Here are the two commentaries that I decided to buy to assist my studying and preaching through the book of Romans. Both are exegetical commentaries (which I highly recommend). One is a technical approach to the meaning of the text (Schreiner), and the other is more of a biblical theology (Talbert). I have learned so much, and enjoy reading these commentaries as if I was in seminary taking a course on Romans. Good reads always lead to good application!