shoe and pedals are all you need.
I will toss in a recommendation of using Crank Brothers Mallets. They are platform pedals and clipless on BOTH sides. I love them as i can ride in work shoes, trainers (sneakers), or clipless shoes.
actually i ride in heavy traffic areas at the beginning of my rides so i dont clip in i ride them like platforms until i get to the MUP or out of the city.
sadly they are heavy beasts of pedals but being in the clyde forum i am not concerned about a few grams. Also there is a 15 degree twist out that some may not like and the tension is not adjustable.
BTW when i went clipless i didnt get faster or more that much more efficient, but for some odd reason i cant go back to platforms?