Ditto. I converted my entire library (> 500 books) to OCR'd PDFs. A local copy shop uses a hydraulic blade to chop off each spine ($1 each), and then I feed through my scansnap S1500M for OCR and storage. Any texts I'm actively working with get attached to an Evernote note (or, if > 20 MB, dropbox) for easy cross-platform access. I scan at 300 dpi and store at 150 dpi after text-under-image OCR. Searching and marking-up resulting PDFs is plenty fast on iPad2 and mac, linux, and windows desktops.