I look at a lot of Android apps, and every once in a while I run across a genuinely useful one. CamScanner is one of those, in that “you may not need it but when you do it is absolutely perfect at what it does” way.
CamScanner turns your phone into a scanner. With CamScanner, you are able to digitize any paper documents by photo shooting. Simply take a picture of any paper documents such as receipts, whiteboards, notes, agreement and so forth, and CamScanner can auto-crop image, enhance image quality and create an industry standard PDF file. And you can easily upload documents to cloud like Dropbox, Google Doc, Box.net, and manage them by tagging or searching.