I used to have a Ballistic case, it was quite good, but I sold it to jrose when I got my
LifeProof case. Being waterproof wasn't super important to me except for when using it on my boat... but it's nice being able to wash it whenever I want, and not having to worry about it falling in the sink (or worse).
If you want something a little more minimal or stylized, my buddies have a company -
Happy Owl Studio - I previously had a leather backing they made that was fantastic. Combined with a bumper case, or something like a
skinomi skin, it's fine for basic knocks and scratches, while keeping the sleek looks.