I absolutely love good key lime pie. Unfortunately even in central Florida it is hard to find a good version of it. I disagree with the statement above that the "crust should be made of crushed graham crackers." True key lime pie comes with a flaky pastry crust, not graham crackers.
All the good key lime pie places in Key West that I know of do not use graham crackers, but it somehow got to be used in many recipes for some reason, and I guess some like it that way. I definitely prefer it with the flaky pastry crust. The frozen versions of it are always easier to do with graham cracker, of course, as it handles the freezing process better than pastry crust. And, of course, the filling should never have a green color to it.