I also carry a Slime kit. It's actually a Roadside Emergency kit as it comes with a first aid kit and jumper cables as well as the air compressor and tire patch stuff. It all fits in a soft case that has velcro on the outside so it sticks to the trunk carpeting and doesn't slide around.
This is the one I have:
http://www.amazon.com/Slime-50051-Al...650327&sr=8-37