I use Speedplay Frog Pedals. Easy to clip in and zero tension to overcome when unclipping. That's why I use them, the other pedals bothered the outside of my knees due to having to overcome even slight spring pressure when unclipping. Have a look, the float is awesome on the pedals, and I can wear mountain bike shoes and walk around without resorting to covers for the cleats.

When you start, I would advocate installing one pedal, opposite the foot you usually put down when you come to a stop. Just do light riding until you get comfortable stopping and starting, over and over. You'll know when to install the other pedal, whatever style you choose. No need to go full monty on the first few days (or months) with clipless pedals.