[DSpider]

I suggest a cheap flatbed scanner, because today's scanners bought from your local brick and mortar store were considered professional-grade only a few years ago. They're great for OCR (even saved as JPG), and good enough for graphics, too. No point in dishing out $1k for a DSLR. Especially if you know how to work in Photoshop and Illustrator, and vectorize graphics such as charts, graphs, line art, chapter decorations, etc.

Focus on quality, rather than quantity. Scanning takes a lot less (~1h-4h, depending on the book) than actually processing it.

My workflow can be boiled down to this: Scan pages with text as JPG (300 dpi, grayscale) and pages with images as TIFF (600 dpi, colour), OCR in ABBYY FineReader Pro, proofread it, export as RTF, run my own macro that removes the styles and everything else, track down the fonts, process/vectorize the graphics, import the RTF into InDesign and redo the layout, proofread again the final product (basically I read the entire book twice in the process).

The result is usually of a very high quality and it's always a pleasure to read such a book. But not many people are willing to put in the time and effort - it can take up to a month if I work on it 2-3h each night. Lastly, make sure that the content is worth it, and that it's not already available as an e-book.