The Zondervan Illustrated Bible Backgrounds Commentary Set: Old Testament is scheduled to be released in November. This five-volume set provides textual and pictorial commentary on every book of the Old Testament. Edited by John H. Walton, the set is 3,000 pages long and includes more than 2,000 photographs. I have not yet seen it advertised, so I thought I’d mention it here. Amazon currently has the best price at $157 (list: $250). The New Testament set came out in 2002.
UPDATE (8/26): The Koinonia blog (Zondervan) has been running a series of excerpts from this series since January.