My favorite niche Andriod apps

Did you take my advice and pick-up a Nexus 4 for yourself, or for someone who might not be a phone geek?  So if you've spent any time with the phone, you're already using the mainstream apps (e.g. the Pandora, Dropbox, Skype, OpenTable, GasBuddy, etc.).  But what about the niche?  The ones that you didn't think to think about?  Well, here are a few of my less mainstream favorites...

• Tape-a-Talk - great little tool for taking voice notes (like for a class, or if you want to record long rambling thoughts for later dictation).  If you even begin to build up a back-log of voice notes, you'll find the paid for version is critical to keeping your thoughts organized.
• Power Note - if you use Diigo for social/cloud/portable bookmarking needs, Power Note comes in quite handy for interacting with your library while mobile.  
• Handy Scanner - Scan things like receipts, and send them to DropBox.  
• AirDriod - Enables you to wirelessly manage your phone from your computer.  If your phone and computer are on the same network (or with the latest release, even if they're not) you can connect via a web browser on your computer to get a desktop-like experience for navigating your phone (copy files, send texts, etc.).  I mostly use it to transfer files when I don't have a USB cable handy. 
• Compound Interest Calculator Basic - because who doesn't like to be able to calculate the opportunity cost of small financial decisions from their phone?
• Wallpaper Changer - such a cool little app for rotating through pictures as wallpaper... here's a link directly to the developer.

Obviously, the you can search your way through the vast Google Play store to find useful things.  But these are some of my favorites.  If you have an amazing niche app to share, or something better than the above let me know about it.