I bought a Trident Kraken - very tough and durable 3 part case but it is enormous and the rubber outer shell makes it tough to get in/ out of shirt/ jacket/ pants pockets.
I used the Kraken for a month before the size of it started to bother me.
I then moved to an Otterbox Commuter, while not as hefty as the Kraken has held up very well. Its slim enough to get in/ out of my pockets. Its a 2 part case, inner shell is rubber with a poly outer case.