Looking on Amazon, the iPearl that ClayMac has is the highest rated with +500 reviews at 4.5 stars. Speck and Kuzy cases were both at a solid 4.
Take a look around on there and see if you can't find something that catches your eye. Also, you need to decide what sort of finish you want on the case. Some are a solid hard plastic, others are more rubberized that will feel softer and provide more grip. And as a little bonus with the iPearl, those extendable legs also help keep the MacBook a little cooler since air can circulate underneath it.