Strong leadership, no matter how well intentioned and benevolent, can foster dependency and subvert democracy. Yet absence of any leadership can lead to confusion, drift, and tension. Every organization will solve the problem of leadership in a different way. They have no formal leaders and few overt signs of leadership behavior. Other groups do well, at least for a generation, with a single central leader who encourages the members to participate.
Many successful groups find middle ground.
All members take some responsibility for making the organization work. Here's what we at GEO try to do when in a leadership position. Instead of imposing someone's proposal quickly, we try to figure out how each member can have a role in reaching a decision, and feel that her role is valued. Knowing that some members have more expertise in given areas, we'll give more weight to their views in making decisions in those areas. But everyone can help the group come together to make a decision that all members can stand behind.