SP2010 daysandnight.master does not have top navigation.  to make it work simply add the following element just before the Ribbon Div.

<div class="s4-lp s4-toplinks">
                        <asp:ContentPlaceHolder id="PlaceHolderTopNavBar" runat="server">
                                <asp:ContentPlaceHolder id="PlaceHolderHorizontalNav" runat="server">
                                    <SharePoint:AspMenu
                                      ID="TopNavigationMenuV4"
                                      Runat="server"
                                      EnableViewState="false"
                                      DataSourceID="topSiteMap"
                                      AccessKey="<%$Resources:wss,navigation_accesskey%>"
                                      UseSimpleRendering="true"
                                      UseSeparateCss="false"
                                      Orientation="Horizontal"
                                      StaticDisplayLevels="2"
                                      MaximumDynamicDisplayLevels="1"
                                      SkipLinkText=""
                                      CssClass="s4-tn"/>
                                    <SharePoint:DelegateControl runat="server" ControlId="TopNavigationDataSource" Id="topNavigationDelegate">
                                        <Template_Controls>
                                            <asp:SiteMapDataSource
                                              ShowStartingNode="False"
                                              SiteMapProvider="SPNavigationProvider"
                                              id="topSiteMap"
                                              runat="server"
                                              StartingNodeUrl="sid:1002"/>
                                        </Template_Controls>
                                    </SharePoint:DelegateControl>
                                </asp:ContentPlaceHolder>
                        </asp:ContentPlaceHolder>
                </div>

Make sure you remove the PlaceHolderTopNavBar and PlaceHolderHorizontalNav from invisible PlaceHolder from the bottom of the master page.