I use Paperless iOS app, synchronized with Dropbox.
<a href="http://crushapps.com/paperless/" rel="nofollow">http://crushapps.com/paperless/</a><p>Usual stuff: groceries, travel packing list, travel bucket list, ideas, restaurants to go to, date ideas, hiking trails, places to notify about address change, wishlist (things to buy), books to read (separate list for fiction and non-fiction), gift ideas, beers, wines, document checklists for more or less complicated things like mortgage or visa applications, conferences.