Just one other point. You don't have to use the slime with the kits. I also carry a simple tire repair kit so you can just pull the object out of the tire, plug the tire, then use the pump to re-inflate the tire and you're on your way. Plugs aren't supposed a permanent fix, but they'll easily last several thousand miles until you can get the tire to a repair shop.
I'll do anything to avoid carrying a spare tire in that already fairly small trunk for insurance against something that happens once ever ten years.
http://www.amazon.com/Slime-1034-A-T...2WP01B1GQJ9XY4