I'm currently riding on 700x28 Continental Gatorskins. No flats since I put them on 600 miles ago.
When I *do* get a flat, though, they will be HUGE pain to work with. The bead is insanely tight, and I could not get the tire on the rim without jamming it on with a tire lever or two. When mounting them, I punctured two tubes before I finally figured out how to get it on over the rim.
I flatted on a different bike the other day, and could get the tire on and off without using a tire lever at all. It was wonderful. But I get a lot more flats with those tires.
What's a good compromise between puncture resistance and ease-of-getting on and off?