Sean Reid offers up my favorite argument so far in the does-your-camera-matter debate.
Its true that the tail shouldn't wag the dog. It's true that photographers and pictures are more important than cameras and lenses. It's true that hours spent studying photographs and paintings themselves will often be far more valuable to a photographer than hours spent worrying over what equipment to buy next. Its true that many have been conned by decades of advertising into believing that becoming a good photographer is mostly a matter of buying the ‘best’ cameras and lenses. It's true that there is no such thing as a ‘best’ camera or a ‘best’ lens for all photographers. Its true that we generally do not need the newest and most expensive cameras and lenses to make strong pictures. That's all true.
But its not true that cameras and lenses do not matter. There is no best camera and no best lens, globally, but there may well be a combination of camera and lens that best suits a specific photographer for a specific set of work. It might be a combination that costs forty dollars or forty-thousand but whatever it is, it can play an important role in the creation and look of a given photographers’ work.“