A oldie this one but always useful.

When you create a webpart page on SharePoint 2010 or 2007 for that matter, the quick launch disappears… (oh bummer).

With SharePoint 2007 all you needed to do was edit the page in SharePoint Designer and remove the following 2 lines:

< asp:Content ContentPlaceHolderId=”PlaceHolderNavSpacer” runat=”server”></asp:Content>
< asp:Content ContentPlaceHolderId=”PlaceHolderLeftNavBar” runat=”server”></asp:Content>

With SharePoint 2010 you also need to delete the following:

< style type=”text/css”>
body #s4-leftpanel {
display:none;
}
.s4-ca
{
margin-left:0px;
}
</style>

The quick launch will now display on the web part page.