I rate the modern bicycle among the greatest of all human inventions. Perhaps its simple design and ubiquitous presence deceive us regarding its importance - a device that allows us to propel ourselves under our own power at super-human speeds over great distances with minimal effort.
As for the comment above concerning clipless pedals: they are indeed superior in many applications, and I have a set for my own bike. But a serious drawback is that you must wear matching footgear, that is typically not good for walking any distance off the bike. They also discourage using the bike for quick "jump on and go" situations, since you've gotta first put on the matching shoes.
My own solution for daily bike use is a pair of the older-style toeclip pedals. They accept any shoe or even sandal, but still give many of the advantages of better foot control and pedaling efficiency. You'd be surprised how much more force you can apply to the pedal when you don't have to waste energy with holding your foot steady on an open platform pedal.
You can buy complete pedals, or just the toeclips, for use with or without straps that can be installed on your existing platform pedals if they have mounting points. This is what my bike has for daily use, with another set of clipless pedals I swap out for longer rides.
It takes a little while to learn how to flip the pedal over and insert your foot into the toeclip (since gravity makes them hang upside down when not in use, unlike what this photo shows), but not a greater learning curve than using clipless. I've been using toeclips since 1962.http://www.google.com/search?client=safari&rls=en&q=toeclip+pedals&ie=UTF-8&oe=UTF-8#q=toe+clip+pedals&hl=en&client=safari&rls=en&prmd=ivs&source=univ&tbs=shop:1&tbo=u&ei=mmDETN6_OcP7lwer0KAF&sa=X&oi=product_result_group&ct=title&resnum=1&ved=0CDkQrQQwAA&fp=499faa430ac3503f