Grayscale images take up significantly less room on your hard drive than color images do, and if the original is already black and white, scanning in color has absolutely no value. Well, Line Art is a great way to scan images like coloring book images and is required for OCR in some scanning software. OCR stands for Optical Character Recognition which is used to scan documents and convert the scanned image into text. This is very useful for slow typers who need to duplicate a document. There are problems with the process though.
Some character are misread.
OmniPage one one of the better OCR software packages out there today. The other major issue you'll need to address is scanning resolution. To decide on the proper resolution, you'll first need to determine exactly what you'll do with your images. In fact, you probably don't need to scan any higher than 150 dpi. This may seem odd, considering your Inkjet printer probably prints at 600 dpi or more.