it depends - how do you use your phone?
for example - if you know you will drop your phone, then otter box and the like are they to go.
for me personally - I'm extremely careful, the chances of me dropping my phone are very slim, but on the other hand, I do care about cosmetic damage, so my favorite is the apple silicone case - it offers only basic drop protection but it leaves almost no area of the phone exposed, and has microfiber lining that traps dirt and prevents it from scratching the phone