Personally the case-mate "pop" case works best I think. It doesn't add much bulk while giving sufficient protection. I've looked into the commuter case but I've heard with the extended battery it doesn't line up quite right or there are "gaps" in certain places.
That's correct. I have the extended battery on my GNEX with the Otterbox Commuter case and it doesn't quite fit exactly. The top lines up but the bottom of the phone doesn't. It doesn't interfere with the flaps for the charge port or headphone port but you can notice it. I've lived with it as long as I can which is exactly why I'm in this forum looking around.