OD Otterbox. I bought an FDE Magpul case, but don't use it because it doesn't have a screen cover. I don't like the bulk of the Otterbox, but I do like not having to worry about scratching my screen up.
I have a standard slip on rubber case. It works just fine for what I do. I had an Otterbox for about 5 minutes but i didn't like carrying a brick around. I do have an Otterbox on my Samsung Tab.
Im gonna grab one of those magpul ones this week though. The otterbox is getting a tad cumbersome...and its hard to scratch a screen on an iphone. I work in a shipyard and ive never scratched a screen without the OB on. Keep my phone in a bag so burrs and grinding grit dont gunk up my speakers.