After installing android with eclipse it came along many versions. some people recommended to use v2.1 and v2.2 and not v2.3 since it is not supported by many devices.
Is the idea of using the latest edition (2.3) good? Which one do you recommend?
what about programming wise rather than audience wise?
It depends what your target devices are for your app. Usually you’ll want to target Android 1.5 if you want to cover all devices. Targetting 2.1 will still give you about 90% device coverage and is better if your app is very performance heavy; 1.5/1.6 devices are on the low end and probably wouldn’t run these types of apps well anyways.
This page shows the distribution of Android devices and their OS versions that are currently out there.
http://developer.android.com/resources/dashboard/platform-versions.html