Tire repair kit + air compressor + Fix-a-flat spray tin.
Also I've had mine for 10 years, 230000 km and no flats. I even had a screw in the tire for several days of driving and didn't realize it until I got home. When I removed the screw at home the tire deflated right away.
Initially, I was really concerned about having no spare. Now I don't even think about it.
2009 Saffron Elise
1986 Toyota Tercel - RIP Oct 20/2012