One of my top favorites, and most used apps is Evernote. It is basically an information repository and manager where you can store bits and pieces of information and a lot more and later find them easily using search and tagging functionality. Most important of all its free [premium upgrade available with a lot of additional features] and syncs to the web so that you can access the data anywhere. Now isn't that worth a look? :)
It’s easy as creating a free account and installing the application in your desktop or Smartphone. Versions for iOS, Android, BB, Windows Phone, Windows, Mac etc are available and you can use multiple simultaneously and be ultra productive. In my case I use it on my iPod Touch, iPad, Web, Windows Computer as well as Macbook Pro. This kind of omnipresence makes it a companion you will never forget, and if even forgotten you might have one or the other device near you to get into it. Evernote has public API's which other developers can use to integrate it into their applications. For common people, this means you can use multiple apps that integrate into Evernote and act as your information repository.
Evernote has a lot of cool features you will like and I can speak volumes about each. Here is a short intro into some I use the most.
