I put my car key on the key ring, my house/other keys in the zipper compartment (I don't need to use those much), and my Starbucks card/other card in the exterior pocket. There's plenty of room in the little pocket for change in addition to my keys. I'm in the minority, but I love this little gem.
I posted with the SBs card in the exterior pocket, and also showing that they don't fit in the zipper compartment.