i cracked my screen on day 8 of my unlocked n7100, then a couple of more drops later, apparently broke the proximity sensor. One thing to try is to get insurance from squaretrade. i got one and going to wait before i submit my claim, but i was told that you have to tell them that you accidentally dropped it, otherwise if you just say it fell off a table they wont honor it. weird right? but maybe this will assuage you after plunking down good coinage for this device.
that said, a good case is definitely needed. i got a big wallet type one. although it adds bulk to the device, at least its ok when dropped. i've since dropped it on tile and marble flooring and no issues. Knock on wood. with your hands, not the gn2. =D