My setup is pretty simple. I just stick with the tried and true. A genuine Apple Smart Cover for the front and a nice Caudabe Shell for the back. The Smart Cover I paid full price for. Not cheap, but I like the quality and it works really well. I know some friends who've bought cheap knockoffs on Amazon, but they're clearly inferior in quality.
The Caudabe Shell is just a simple hard shell, but it feels really nice (I got the frost clear one) and is a good deal for the money: http://www.amazon.com/gp/product/B009RN10KK