I'm writing a HTTP client which doesn't have any encoding algorithms built into it yet. Therefore, I was wondering if there is a value for Accept-Encoding header to indicate this? like: "none" for example, or "text/plain" or similar ?
You can just omit the Accept-Encoding header if you don't support compression:
http://www.httpwatch.com/httpgallery/compression/
However, this will not prevent some servers sending you chunked encoded responses:
http://www.httpwatch.com/httpgallery/chunked/
on persistent "keep-alive" HTTP connections. You can disable persistent connections by adding a "Connection: close" request header and the server will simply close the connection after all the content has been returned in the response message.