Just in case you ever wanted to use the .NET Zip Library to receive GZip-compressed content from a webserver, as well as sending a custom UserAgent string to identify your app, here's how you do it:
        /// <summary>
        /// Used to send out a custom application UserAgent, and return a string from a GZip-compressed
        /// response.
        /// </summary>
        /// <param name="strUrl">The url you want to retrieve.</param>
        /// <returns></returns>
        public string GetWebRequest(string strUrl)
        {

            StringBuilder mySB = new StringBuilder();

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(strUrl); 
            // Sends the HttpWebRequest and waits for the response.  
            request.UserAgent = "BSClient 0.3";
            request.Headers.Add("Accept-Encoding", "gzip, deflate");
            HttpWebResponse response = (HttpWebResponse)request.GetResponse(); 
            // Gets the stream associated with the response.
            Stream receiveStream = GetGzipStream(response);

            Encoding encode = System.Text.Encoding.GetEncoding("utf-8");
            // Pipes the stream to a higher level stream reader with the required encoding format. 
            StreamReader readStream = new StreamReader( receiveStream, encode );
            Char[] read = new Char[256];
            // Reads 256 characters at a time.    
            int count = readStream.Read( read, 0, 256 );
            while (count > 0) 
            {
                // Dumps the 256 characters on a string and displays the string to the console.
                String str = new String(read, 0, count);
                mySB.Append(str);
                count = readStream.Read(read, 0, 256);
            }
            // Releases the resources of the response.
            response.Close();
            // Releases the resources of the Stream.
            readStream.Close();

            return mySB.ToString();

        }

        /// <summary>
        /// Used in place of GetResponseStream().  This function will check out your HttpWebResponse's contents,
        /// and return the proper string representation of the HttpWebResponse stream.
        /// </summary>
        /// <param name="response"></param>
        /// <returns>String representation of the HttpWebResponse</returns>
        private Stream GetGzipStream(HttpWebResponse response)
        {
            Stream compressedStream = null;
            if (response.ContentEncoding=="gzip")
            {
                compressedStream =  new GZipInputStream(response.GetResponseStream());
            }
            else if (response.ContentEncoding=="deflate")
            {
                compressedStream = new InflaterInputStream(response.GetResponseStream());
            }

            if (compressedStream != null)
            {
                MemoryStream decompressedStream = new MemoryStream();
                int size = 2048;
                byte[] writeData = new byte[2048];
                while (true)
                {
                    size = compressedStream.Read(writeData, 0, size);
                    if (size > 0)
                    {
                        decompressedStream.Write(writeData,0,size);
                    }
                    else
                    {
                        break;
                    }
                }
                decompressedStream.Seek(0, SeekOrigin.Begin);
                return decompressedStream;
            }
            else
            {
                return response.GetResponseStream();
            }
        }