I'm what you might call a case whore.
Otterbox Defender- This case gets way too much credit for what it is. It does fit the extended battery but that is about the only good thing it has going for it. The front of the case goes all the way up to the viewing portion of the screen and some have reported that it scratches the phone which makes the built in protector pointless. The clips that hold the case together are not quality at all and will crack and break off after the first few removals. The part I hate most, is that the silicone is on the outside. This case is not worth the $50.
Otterbox Commuter- This is everything the Defender wishes it as. Very nice silicone on the inside of a hard shell. It even has better port covers than the Defender.I have also heard that the Seidio spring clip holster fits it nicely. It does not fit the extended battery.
Verizon case/holster combo- A nice case if you do not care about dropping your phone. Might as well go naked. The case does not protect the top, bottom, corners, or screen. It will not fit the extended battery.
Cruzerlite Androidified- Very nice TPU case. You have to be carefull putting it on as it fits so snug it will bunch up your screen protector. It feels really nice in hand and adds very little to the phone. As a bonus they look cool as hell, especially in Android green. This will fit the extended battery. I got min for $10 each.
Trident Kraken- If you need protection and are considering the Otterbox Defender, STOP. Get this instead. Has a very nice inner silicon layer, which can be used as a case on its own, Surrounded by a beefy two piece hard shell. The clips that hold it together snap like legos. It has port covers, fits the extended battery and has a kickstand that can be swapped out for a bike clip, car mount, tripod and a number of other things. At $32 I can not speak more highly of this case. The only issue with it is that it covers half of the notification light. Hopefully this will be revised in the future.
I'm also going to pick up a Ballistic Shell Gel but I don't think it will have what it takes to replace the Kraken.