anyone riding their "good" road bikes with flat pedals?

[kiwisimon]

I have my road bike with Time Xpresso pedals and Sidi shoes. Walking is pretty much not something I do unless it's the 3 meters from the house to my bike and back, or I have to get off mid ride for some reason (dropped something or someone else did).
I usually ride the 25kms (semi rural) to work and change into casual shoes there.
Mondays(and bad weather/road days), I ride the heavier fendered bike( time Atak pedals) with panniers to carry in my change of clothes for the other days, .

Sometimes I have errands about 10kms away and I take the road bike for the 25-30 minute urban ride. I can ride with the current setup but being in Japan removing cycling shoes to go inside a business for a one minute stop is not that convenient. Thinking about using flat pedals.
I haven't ridden with my feet not clipped/strapped in since the early eighties.
Does anyone here ride a road bike at a good pace with flat shoes?
What pedal and shoe combinations work best? FIA..