After putting on more than 1000km without one single flat tire (minus accidental damage done to a Presta valve), I'd suggest my combination of Michelin Pilot tires with Protek Plus and Joe's No Flat tubes along with the best quality rim tape you can get. A bit heavier than your normal combination, but the tires keep their pressure a-lot longer. On the downside, the Joe's No Flat tubes need changing every two years and if you don't use your bike often, make sure that the valve is above the 9 and 3 o'clock position so the foam/jell won't clog it.