I've put together a list of basic reference books for understanding God's word. A kind of starter library for reference. The aim is that you'd be able to pick up any book of the bible and get the basic answers to your questions. E.g. Where is the place, when was the book written, what else does the bible say on the topic of e.g. the kingdom of God, etc.
1. NIV Study Bible
Just brilliant. It's got all the basic charts, maps and dates you need as well as basic comments on each verse of the bible. I can't recommend this highly enough. I also have the ESV Study bible but if I had to choose I'd go with this one.
2. Essential IVP reference Collection 3.0 (Electronic edition - Logos)
This computer based set is great. You get 17 books for this price. The main reason to get it is the 4 new testament dictionaries it comes with. They look at almost any new testament topic and look at it in each the gospels, then Paul's letters and finally the remaining letters of the NT. These are fantastic! It's also got a one edition bible commentary as well as interesting dictionaries. It includes an atlas.
You can buy it from CBD for $120 delivered worldwide.
3. The Bible Speaks Today - Complete NT (Electronic Edition - Logos)
This set is edited by John Stott and he actually wrote many of the NT ones most notably Ephesians, Galatians, Thessalonians, Acts and Romans. The series is fantastic. It's got enough of the historical and cultural background stuff to know what it meant to the original heares, it's also great on theology and then gives some very helpful application. But above all they're written by men who really love God. I've found them very helpful in preparing sermons.
You can get the complete NT set from CBD for $75 delivered worldwide.
4. Tyndale Complete Old & New Testament Commentaries (Electronic Edition - Logos)
These commentaries are relatively short but cover all the books of the bible. They are often recommended (especially the OT books). But for this price you get commentary on every book of the bible.
You can get the complete OT & NT set from CBD for $160.