Samsung Galaxy Gio. By default, running Android 2.3.3 I believe. A terribly slow device, a hell to use. That is, until I flashed it. It is now happily running CyanogenMod 10.1, based on Android 4.2.2. A device which I completely love. I don't even have a reason to switch, even though my dad will probably get a new phone soon and, seeing how he hates smartphones, that will probably end up being my next phone.