I am building a website for a client who needs a content management system to go with it. The client requires features such as content staging, approving process before publishing a page, provision for templates (changing which changes the lay out for the whole website), entry and expiry dates for pages and content search. I am planning to use an existing opensource CMS for the work but I am confused as to which one should it be. I need help in deciding whether this approach is good or should i develop my own CMS? and if I do use an opensource one, which one is extensible and customisable enough using .NET?