Milton Stanley at Transforming Sermons has started a chain where preachers (and in my case want-to-be preachers) are listing their five favorite resources for preparing for preaching. I'm glad Joel Olsteen was listed by the Jollyblogger since I have not read him yet. But Stanley here are mine.
Ideally I like to translate the passage from the original languages and I use a variety of Greek and Hebrew resources.
1. The Interlinear NIV Hebrew-English Old Testament By John R. Kohlenberger III
2. The RSV Interlinear Greek-English New Testament By The Reverend Alfred Marshall. (Gift from a friend).
3. I also use Bible software - right now I'm using the Sword project on my Linux box so I've been using BibleTime for KDE. I'm not really impressed with their interface so I'm in the process of experimenting with Bible Desktop.
4. I use a commentary. One of the series I'm buying one at a time is Tyndale Old Testament Commentaries (IVF). Since when I'm preaching, I'm preaching through 1 Samuel I'm using Joyce G. Baldwin. (That's right a woman. Her commentary on Daniel is good too.)
5. English Standard Version
5 plus one - Addam Clark's Commentary An elderly preacher in Missouri gave me his copies before he passed away. Though they are old, their great.
5 plus two - Treasure in Scripture - The most extensive cross reference list I know of.