If you can accept its limitations, SwiftKey Note's robust predictive keyboard and clean design make it a must-have for taking notes.
Whether you're a regular Google+ user or just interested in the app's photo-editing or auto-upload features, Google+ for Android is a must-have.
Better than Instapaper and other competitors, Pocket is the app to beat when it comes to bookmarking and managing links.
GarageBand is the best app for music creation on a touch screen. With real-world instruments, true-to-life sounds, and tons of easy-to-use tools, there is simply no other app in its class for iOS.
Pandora Radio is not only easy to use, but it's also scary good at getting to know your musical taste. Download it and start creating stations as soon as possible.
Polished graphics and sound design along with excellent puzzle-solving gameplay make this sequel well worth the price tag.
With its solid performance, beautiful design, and nifty picture-in-picture, it's hard to argue that there's a better way to watch YouTube videos on your mobile device.
If you're a more serious mobile photographer looking for an app to fine-tune your photos with, Snapseed is your best choice.
If you have a mobile device running Windows Phone version 7.5 or higher, then SkyDrive is a must-have.
Air Patriots is a unique tower defense-style game that strikes just the right balance between challenging and fun.
With its clean design, new picture-in-picture features, and improved browsing, it's hard to argue that there's a better way to watch YouTube videos on iOS devices.
There are tons of image editors in the App Store, but PhotoToaster is easy to recommend with a slick and simple interface, helpful menus to get you started, and extremely impressive results.
If you like a serious challenge, this racing game has all the bells and whistles, offering plenty of free content and several tracks to thrill and frustrate you.
Fast and exciting strategic gameplay makes Kingdom Rush Origins a must-have pick for tower-defense fans.
Advanced photo editing features and tons of artistic tools for creating and editing images make Pixelmator a must-have for photo enthusiasts and well worth the price.
With its long list of features, zippy performance, and syncing of data across other devices, Google Maps is a must-have application for anyone running Android.
Plants vs. Zombies 2 is a must-download, with new plants, new ways to play, new challenges, and a freemium model that doesn't get in your way.
Pandora's easy-to-use interface and massive music library make the app a must-download for music fans with Windows phones.