I stumbled across this really interesting web site that lists just about every modern commentary written about the Bible: BestCommentaries.com.  You can search by OT/NT book, commentary series, and author.  It also lists tons of ‘forthcoming’ volumes as well.  Each commentary has a ‘tag’: academic, pastoral, devotional, and/or special study.  The sort functions and favourites lists by different people is also handy.  A couple of drawbacks are that 1) it only lists english language commentaries and 2) it does not list commentaries for the Apocrypha and the Pseudepigrapha.