nobody has mentioned yet, in ASP.NET 4.0 there's new syntax to do this. instead of
<%= HttpUtility.HtmlEncode(unencoded) %>
you can simply do
<%: unencoded %>
read more here: http://weblogs.asp.net/scottgu/archive/2010/04/06/new-lt-gt-syntax-for-html-encoding-output-in-asp-net-4-and-asp-net-mvc-2.aspx