there are essential apps then popular ones see this list
Apps: The Most Downloaded
Developers are fighting back with some developing products which are currently on all the three major platforms: Android, iOS and Windows Phone 7.
Read more: http://www.gadgetrophy.com/p/apps.html#ixzz1YN1pLrKo
Most Downloaded Free Android Applications.
This are some of the Most Downloaded Free Android Applications available on the Android Market for Android Device
Read more: http://www.gadgetrophy.com/2011/09/most-downloaded-free-android.html#ixzz1YN2DXRKz