Google Nexus: Has access to the Android App Store, and Google Play, which allows purchasing of music and movies.
iPad: Apple leads the market with more than 500,000 apps.
Kindle Fire: The Amazon Appstore for Android listed more than 17,000 applications.
Surface: Will run Microsoft Office. Also, the device will run Windows 8, which allows developers to create applications.
Pictured: Apple chief executive Tim Cook discussing apps.