I found an old Giant "Option" ATB and built it up as a tourer. I've commuted
to work several times, did two metric centuries on it, and numerous +20-mile
"run-around-town" rides. It's sporting 700x35mm touring tires (traded out
the 27" x 1 1/8") that give a fair decent ride without too much rolling
resistance. They also hold up well on gravel hike & bike trails, dirt paths,
and uneven sidewalks. A skinny tire at 90 or 100 psi would blow on some of
the stuff I ride on, but at about 50 psi, 35's roll right over 'em. Except
2" high rises in the concrete...

Flats are one of the constants of the universe...as far as mechanical
trouble, just keep your bike maintained, and you shouldn't have any
problems.