Originally announced as a preview during Google I/O 2013, Android Studio, the official IDE for Android apps development, is finally on version 1.0. For the list of new features, you can check the announcement in the Android Developers blog and the Android Studio Overview.
If you haven't tried the previous versions of Android Studio can be, you should start using it now! Android Studio can be downloaded at http://developer.android.com/sdk/index.html. If you are migrating from Eclipse IDE, read the migration guide.
Also, please spend a few minutes to fill up the Android Studio 1.0 Developer Survey here.