I am basically forcing the "File Download" dialog box for both known/unknown MIME types(doc,pdf,zip,tar etc) related to the Microsoft article
http://support.microsoft.com/support/kb/articles/q260/5/19.asp
and streaming the data.
Response.AddHeader "Content-Disposition","attachment; filename=test.pdf"
Response.ContentType = "application/pdf"
Response.CacheControl = "public"
and steaming code...