As a preface, I would like to state a few things before answering your question. Human society does not develop in a linear fashion, and I caution against attempting to place certain societies above others. In cultural anthropology and archaeology, there is a now entirely rejected school of thought known as unilineal evolution. This school boils down to considering Western culture to be the pinnacle of human society. All groups of people would, provided the right circumstances were in place, eventually resemble Westerners. Thus, Australian aborigines or African aboriginal groups, for example, were simply an earlier stage of development for society (one which Western society had already passed). Although completely rejected by current academics, I find elements of this school of thought to be still somewhat pervasive today. It is inappropriate to label hunter-gatherers or those without modern technology as less socially developed. Furthermore, I find it fruitless to use the term development with culture, as it implies an inherent hierarchy to cultures, and this hierarchy is typically generated by viewing foreign cultures through biased eyes.
As for your question, metal is absolutely unnecessary for a culture to flourish. In general, the pre-Columbian Americas abound with examples of widely varying cultures. There existed the well known Aztec, Inca, and Maya civilizations if you are interested in cultures that exhibited social stratification, monumental construction projects, widespread agriculture, and built large cities. The Eastern Woodlands of what is now the United States teemed with widely varying cultures ranging from nomadic hunter-gatherers to horticulturalists and agriculturalists. A neat example of a hunter-gather society that exhibited levels of stratification and public mobilization for events and projects that we typically associate with sedentary agriculturalists is the Tlingit of the Pacific Northwest. The story for them is essentially that the region was so overflowing with food and raw materials that agriculture wasn't really necessary to support high population densities.
To close, we can certainly draw trends as to how cultures will respond to technological innovations or environmental obstacles. A reliable source of food is certainly important for a culture to really flourish, but the source may take many forms. It is important to remember that agriculture is not inherently superior to hunting and gathering. For many years (and in parts of the world today), mankind lived in fear of droughts and pestilence ruining the year's crops. Additionally, the adoption of mass agriculture often led to a decline in health for people as the diet came to consist of a relatively small number of crops that did not fully meet nutritional requirements. The archaeological record is rife with the skeletons of agriculturalists exhibiting all kinds of nutritional disorders. Also, infectious disease followed agriculture once population densities increased and people became more sedentary. It wasn't really until quite recently that agriculture afforded a really well balanced diet.
Aside from the Wiki links for some basic background, I can recommend a few books for you if you are interested.
Cultural Anthropology: An Applied Perspective by Ferraro and Andreatta is an excellent intro book for cultural anthropology, and many of the concepts I discussed are elaborated upon.
Ancient North America by Fagan is a solid overview of the prehistory of the NA continent.
Ethnobotany by Minnis is a book I absolutely love. It is a collection of case studies of the adaptations various peoples have made to their environment. People are so incredibly adaptable and resourceful. It can really demonstrate how sometimes strange, quirky, or seemingly useless/old fashioned traditions are actually cultural adaptations that, for example, will boost crops yields or provide buffers against nutrient depletion or droughts.