Scott Guthrie has a post on his blog on how to get jQuery intellisense working correctly in Visual Studio 2008 here. No more hacks like

 <asp:PlaceHolder runat="server" Visible="false">
        <script type="text/javascript" src="js/jquery.intellisense.js"></script>
    </asp:PlaceHolder>

 I swear Scott has an army of gnomes working for him, I can never figure out how he manages to do so much stuff at once.