The Galaxy S2 is likely a great phone in terms of the camera, and certainly in terms of the display, but there's a potential glitch: its predecessor the "Galaxy" is intentionally crippled by Samsung so that it cannot possibly update to Android 2.3. Although some folks that have rooted their phones have done it, the official word from Samsung for the last several months has been..."working on it, but you can buy our new product instead".
The display is amazing when compared to competing products and the camera is pretty good! The potential you can't update the phone to use newer software, and that it will be planned that way to ensure 2013 phone models sell, is something to be cautious of.
On the dura-phone front, I have the Casio Commando, which can swap batteries, is waterproof, shock-resistant and etc... but the camera is terrible.