Windows Authentication and User Particulars

Hi,

I am implementing a new ASP.Net web application using Windows Authentication. Where/how should I be managing individual users' particulars (eg., full name, telephone, email, department, designation, etc)? Should it be in Active Directory? If so, how do I customize the fields, and how do I access the customized fields from my ASP.Net application?

Or should I create a "Users" table in my ASP.Net application, and add all the customized fields + a UserName field which stores the AD username?

Thanks for the advice.