While Min-lun's response will allow you to set the default ranges for all users it doesn't allow you to embed the range in a URL so that you can customize the range for each document using the URL.
 Building upon Ming-lun's response:

1. Open DocView.aspx and add the following above the closing body tag "</body>"

        <script type="text/javascript">
            function getParameterByName(p) {
                var url = window.location.href;
                p = p.replace(/[\[\]]/g, "\\$&");
                var regex = new RegExp("[?&]" + p + "(=([^&#]*)|&|#|$)"), results = regex.exec(url);
                if (!results) return null;
                if (!results[2]) return '';
                return decodeURIComponent(results[2].replace(/\+/g, " "));
            }

            var ranges = getParameterByName('pr');
            $('#PdfDialog_PdfDownloadLink').click();
            $('#PdfDialog_PageRangeBox').val(ranges);
        </script>

2. Save and close.

Now if you supply a URL without the "pr" query string parameter (page range) it will default to the "1-1" page range value. However, by providing the "pr" query string parameter such as :

http://myserver/weblink/0/doc/183289/Page1.aspx?pr=1,3,4-8

will result in setting the ranges variable with 1,3,4-8.

Credit for inspiration (http://stackoverflow.com/questions/901115/how-can-i-get-query-string-values-in-javascript/901144#901144 )

Wes