If you are a casual cyclist who rides on weekends, if the mood strikes you, you might as well skip the special pedal systems altogether. Platform pedals and recreational cycling shoes will meet your needs.
If you’re a serious road cyclist, clipless will give you the most control and power, so it’s definitely the best way to go. You’re also in the best position to stay clipped in, since there’s less reason to stop on a long, endurance ride. Get shoes that match the clipless system you prefer.
If you’re a mountain biker, you could go either way. Clipless is going to give you the best performance. You’ll be able to stay more tightly linked to your bike for jumps, hops and wheelies. But you’ll fall more. If that bugs you, get clips.
Most of all, get shoes that are comfortable. Try them on in the store, make sure they work with the socks you plan to wear and check the heel retention as you walk. Think about how you ride and what you can afford. Then make your choice.