With Enterprise edition you have several server roles.I recommend the "Implementation Guide"http://www.microsoft.com/DOWNLOADS/details.aspx?displaylang=en&FamilyID=1ceb5e01-de9f-48c0-8ce2-51633ebf4714and a blog post about server roles in CRMhttp://blogs.msdn.com/crm/archive/2008/08/20/making-sense-of-server-roles.aspx
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