My "one shoe" of choice is the Xero Shoes Hana in all black, with Footprint Insoles (the flat Hi/Lo Profiles, not the heel-raised Gamechangers or orthotics).
Amazon search: "footprint insoles"
I'll likely be switching to the Vibram Five Fingers Trek Ascent, though, if the thicker sole (compared to the KSO Evos) helps prevent foot bruising on concrete.
I don't give a f**k about the Five Finger look. They're awesome.
(Big Kelly Starrett fan here, on the importance of wearing flat shoes)