I've now been convinced that training wheels have become passe with the growing use of children's balance bikes. Looking across the web, I've been coming across example after example of kids who go straight from riding a balance bike to a normal bike without ever needing training wheels. In fact it would seem that training wheels disable the natural feel or riding a bicycle. The positive effects of learning to pedal and operate a bicycle with training wheels are likely outweighed by the negative aspect of not learning the feel of carving through turns.
Not only are balance bikes great for learning to ride but they are also just super fun for even very young kids. Children as young as even 2 and 3 are able to start playing around on balance bikes.