I'll throw Maxxis Overdrives into the mix, 38mm. Reasonably priced, easy on/off, durable, puncture resistant.

As for the idea of taking a spare, I wouldn't. Instead, take a small kit of Park Tool boots/Gorilla Tape. In the unlikely event of a blowout, that'll patch the tire enough to ride to the next bike shop. A buddy rode three days after booting his Schwalbe Marathon. Use the tape to reinforce the boot, and around the outside.