Get the case from Techshell...
They have some models that are rubberized and don't have the vent's on the bottom like Speck's which allows dirt to get in. They are a bit more expensive but are so much better quality poly-carb construction. I love mine. I have the rubberized cobalt blue one. It's nice to handle, as it gives you a better grip with the rubberized outer coating. They are the only company that makes them like that.