No question you want MTB shoes. But if you do a lot of walking/running you could also look into the "recreational/urban" type MTB shoes. They typically look more like street shoes, have a less agressive tread w/ softer compound, and a more flexible sole (though probably still stiffer than sneakers/clips). Check Shimano, Specialized, etc. "Real" MTB shoes are very walkable, but are fairly stiff soled. Plus the tread is usually a harder compound since they're made to dig into dirt vs. grip smooth ground. But many use them w/ out complaints.