I use Evernote for ebooks, papers, articles and personal notes. Probably wouldn't work well for movies or large photo albums (I iCloud for stuff like that). I use their chrome extension, desktop app and mobile app and it works really well. It's really nice to be able to search everything I've ever written in notes or clipped on the web. It also has some support for OCR for paper notes, and does a decent job of indexing text in PDFs. I searched for an open source or self hosted solution for a long time, but ultimately broke down and chose a well supported commercial solution.