I use Shimano double sided (SPD/platform) pedals PD M324 or PD A530 with Shimano MTB shoes MO76. The shoes have a recessed cleat so you can walk around in them all day. The pedals give you the option of clipless or platform.
I use the same pedals and a laced shoe with the recessed cleat. The sole of the shoe is stiffened so it wouldn't be comfortable to walk in all day, but getting off my bike and going into a grocery store with the shoes on is OK. I carry sandals for walking.