Recommendations for Android app development and test hardware

I’m looking for recommendations for what people are using to get access to development hardware for developing and testing Android Apps. I see th开发者_运维问答ree choices that make sense:

1. Buy Nexus One devices off contract from Google’s developer program (http://www.google.com/phone/detail/nexus-one)
2. Buy used or new off contract devices from Ebay or other sellers
3. Buy devices from carriers with contract and carrier discount

We have a small number of Nexus One’s we’ve purchased and some developers have their own Android phones from carriers, but I was hoping to hear ideas from others. What are you doing to get real hardware for development and testing? we have some application features that don't test well under the emulator, so we need real hardware.

I am also concerned about QA coverage. I see posts like http://blog.tweetdeck.com/android-ecosystem or the variety of devices listed at http://en.wikipedia.org/wiki/List_of_Android_devices and I wonder do you do QA on various devices? Is there a small set of devices could give you better test coverage?