ERP Package Selection

The package selection of enterprise-wide IT systems, which are still increasing in importance for a proper organization support, communication, production and administration of virtually any organization, must be preceded by an extensive process and business audit.
What does the organization actually do, how would the organization like to do based on current best practices? Where did it come from and what future scenarios are there? How sure can you be the desired future scenario will occur and what alternatives do you include in your final choice?