This guy has a few books that, from the face of them, seem very similar. Can anyone point out the important differences or give some advice (e.g. which to pick in what order)?
Information Dashboard Design - is definitely the first one you should read. It really gives a more high level overview of charting best practices and dashboard design.
Show me the Numbers - goes much more in depth about the details of the different chart types and visualization best practices. There's a chapter or two on each of the main chart types.
Now You See It - This is described as a companion book to Show me the Numbers and focuses on data analysis as opposed to pure visualization.