I've been road biking with mountain shoes & pedals (Frogs) for years - before I even had a mountain bike. I have no desire to switch to "real" road shoes. I like being able to walk somewhat normally for rest stops. And I love my pedals, and having the same pedal/shoe combination for both road and MTB makes switching between bikes super easy - I don't have to think about engaging/disengaging the pedals differently.

So whatever works for you!