I used Specialized Armadillo for several years and then switched to Continental Gatorskins, probably 20,000 miles without a puncture. I've had two valve stems break after being on the wheels for years. My friend put Armadillos on his bike and complained that he was having constant flats. Reason: he started out with an old tube that had several no-glue patches. Start with a new heavy-duty tube, and you'll be riding puncture-free. Another thing -- if you ride over glass, stop and check the tires. Glass shards work their way in over time. More info on the Gatorskin tires at http://www.bikenewengland.com/gatorskin.html .