I always wondered where to find all the MIME types and subtypes that you usually set in Response.ContentType property? Yes you can Google it. But I found out today that Windows registry has a registry entry under the HKEY_CLASSES_ROOT just for that. This is where you get a complete list of all legal MIME type/subtypes:

HKEY_CLASSES_ROOT\MIME\Database\Content Type

There are five content types Text, Image, Audio, Video and Application. It is the subtypes that have made the MIME\Database\Content Type very large

Examples found under this registry key: application/msword, application/ms-powerpoint, audio/mpeg, application/pdf, audio/x-wav, application/vnd.ms-excel (for exporting web data to Excel), etc.

Under the MIME\Database, you can also find other goodies such as all the Codepage listing.