It really depends troypolamalu. Some of it depends on road conditions, some of it on the tire and/or wheel, and some of it on just plain luck (or un-luck).

Some of the favorite puncture resistant brands are the Panaracer RibMo's or T-Servs, Schawlbe Marathon Supremes, and Specialized Armadillo's.

The best way to combat flats is to first figure out what caused them.