Either to plain text or editable PDF, like an ebook, so that I can do things like highlight, bolden, and copy words.

you need an ocr program, there's a few available and I think all command line but with separate gui's available

Tesseract (http://kde-apps.org/content/show.php/OC ... ent=121289), ocrad, gocr (gocr-gui) and Cuneiform (YagF)

Kooka the KDE scanning program can use gocr and ocrad as the backend