I am new to the CRM 2011 what is the correct way to add an aspx page because many advises to add an HTML page and a silverlight component to the web resource
is it the best way ?
adding an ASPX Page is not the best way to add custom views on CRM data anymore.
If you only want a custom way to display crm data, using webresources is a better way, as these will also work on offline clients, and are integrated with the solution model -> better deployment experience.
Use the REST endpoint to retrieve and update data in CRM.
Silverlight or not is up to the requirements you have. You can also do a lot if you use HTML and JScript, maybe in combination with JQuery.