I go flats. They allow me to bring just one pair of shoes, one that's generally suitable for riding and hiking (and bar hopping). Approach shoes like the Five Ten Aescent work well, provided you use a good set of BMX-style pedals. There's some loss of efficiency I guess, but very little, and you can move your feet around on the pedals to minimize fatigue over the course of a very long day, negating at least some of the efficiency disadvantage.
I'd certainly not deride anyone's preference, but honestly, I think a lot of clipless devotees would be surprised at how well you can pedal with a good flat/shoe combo. And then you can just get off your bike and walk around like a normal human, since your shoes are no longer "gear."