Started riding with toeclips and straps when I was 15. Went to clip on pedals when they came about when they came out in my early 30's, which I loved because they didn't cut off the circulation in my foot like straps did.

Having said that, I'd recommend that a person taking up cycling would be to get some of the bigger platform pedals that Grant Petersen espouses, and wear some shoes that don't much tread on them. You'll never get knee injuries from having your feet locked in at a bad angle, and you can pedal off the balls of our foot, or move to our heels, or somewhere in between. Last winter I converted my commuter bike to platform pedlas so I could wear some waterproof high tops (Portland consideration to keep my feet dry). It tooks some getting used to, but I didn't notice much of a difference, and stopping at intersections was a lot easier.