Originally Posted by
datlas
I think the OP needs to clarify whether he wants Flat Resistant tires that still ride nicely (eg. Gatorskins, Armadillos, etc), or if he really wants to eliminate flats, which would require the Mr Tufffy Liners, the no-air tires, or solid rubber.
If he wants "the best" in performance and "the best" in flat resistance, the answer is nothing.
Sorry kid, that's life....it's all a tradeoff.
Something like Schwalbe Marathon Plus seems like a good halfway house. They've got a good plastic liner and seem all but indestructible (I've ridden mine over general road debris, gravel etc on a tricross and the MTB version over all sorts of pointy things without anything going through). But on the downside they are heavy, they make a ride more jarring if you hit anything, and they've got a bit of tread on them that an all-out roadie might prefer not to have.
I'm pretty sure you can get them as narrow as 700x25 and maybe 700x23 although they'll test your tyre fitting skills. I had enough trouble fitting my 700x32 to the tricross.