Depending on the situation; when I encounterd flats like crazy due to trashy roads and goatheads I used Specialized Armadillos with Specialized Turbo racing tubes with 700x25 on front and 28 on rear due to major cracks in the roads. Now that I've moved from that danger zone, I now use Specialized All Condition Pro Tire with the same Turbo tubes and run only 700x25. These All Condition Pro tires are much lighter then the Armadillo but the flat protection is still very high-higher then most other tires-though not as high as the Armadillo, but I don't need that much anymore. Plus both tires wear very well.