Galaxy S3 with ArchiDroid installed is one of the best smartphones for the price - very cheap, while having software features most current smartphones don't; ArchiDroid uses Kitkat (Android 4.4.2) which is VERY fast and yet has every software feature you may need.
Galaxy S4 if you like MicroSD slots, but still want the newest phone, and you don't need an FM radio.
Current Nexus if you don't really need MicroSD and removable battery (if money is tight for you, but you still want cutting-edge tech, since it's cheap yet very advanced). Since this is a Google phone, I wouldn't buy it - while even normal androids can be tracked by Google, nobody knows what they do with Nexuses. However, you can at least
prevent them from getting your location without your consent if you dig a little bit.
If you are willing to wait for a month or few, new androids will come out, which will greatly reduce the price of current androids, while new androids will cost as much as current phones. I like Galaxy S5 most out of all that will come out; Sony Z2, like the poster above suggested, is also very interesting.
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As for NSA, NO current technology is safe from them. You can only take a calculated risk by using
Orbot (Tor Proxy) and
startpage.com - you just have to do it, otherwise you may as well lock yourself to prevent any danger coming to you. If you aren't doing something illegal that can bring you a lot of money, I wouldn't worry about it too much since they have a lot bigger fish to fry and, besides, it would be a waste of their time and resources.
Check out my thread
Essential android tools for modern players and alphas to find out how to make your android phone your wingman, or
click here and scroll down if you only need to root it.
Want sound that puts iPods and iPhones to shame?
I got you covered!