I think that the most important phase in the project life cycle is the planning phase. The planning phase is what lays out everything about the project and how to get it done. If this is done correctly then everything else will most likely go smoothly. If planning is done poorly, then its highly possible that something can go wrong in the following cycles. From experience, when you are uncertain of whats going on, and planning isn’t involved; its like going into a project blind eye. I also don’t think that there is a least important cycle; I think that all cycles are essential for the project life cycle because they all contribute in completing it.