I have divided this book list by priorities:
I. Essential
A. The King James Version of the Bible, or - at least one of the KJV updates at the very least. The rest of the translations are Dreck.
B. The Book of Concord. The Triglotta is the best edition. Tappert is a good portable edition. The Book of Concord is the best one-volume Biblical commentary available.
C. Luther's Sermons. It is better to have a small usable set than to leave all of Luther unread, unless you want to be a Lutheran leader. The synod leaders and professors are ignorant of Luther - that is a definite career path today. Here are some of them on the Net. This inexpensive set contains the Lenker series and Klug set, all for the cost of dinner out.
II. Wish List
A. Lenski's commentaries are the best single source for doctrinal issues, grammar, and translation problems. His introductory material alone makes the set worthwhile. He does not teach forgiveness without faith (UOJ).
B. Any book by Chemnitz. Once again, reading is better than just owning. Depending on your doctrinal interest, buy one volume and read it carefully.
C. Krauth, H. E. Jacobs, and Schmauk - all three fought the Confessional battle in the Muhlenberg tradition. The anti-Confessionals ultimately won, leading to the ELCA of today. Could these men get a job in ELCA today? No. Do you think your synod is not sliding downhill fast? These books often appear in used book offerings and library sales.
D. Robert Preus, Justification and Rome. The UOJ Stormtroopers will not admit that he repudiated their precious doctrine. ELCA loves UOJ, so the obvious apostates were happy to compromise with Rome about justification.