Pyrethrin dips are quite successful at being mild, safe, quick flea-killers. They are a quick pre-emptive strike and give several day's residual power. They are less hassle than shampoos and dips and work very well in between baths as a flea deterrent. Your well-stocked arsenal should probably contain a spray. Many have harsh and potentially dangerous chemicals, and their placement around the neck can lead to serious compromise of the nervous system if improperly used or mixed with other toxic agents.
Permethrin collars are the best approach.
Spot Treatments are the new front line in the flea battle. The best will also help prevent re-infestation by rendering the fleas unable to reproduce. But, be careful. More expensive is not always more efficient. The battle against fleas is matched only by the battle of the giant manufacturers to lower the prices of the spot-on products.