At a client we designed a custom homepage for their intranet, containing news in categories and a flashy Silverlight picture rotator. We had a problem with the site logo however. On every site the custom logo would appear, but on this page, which was a webpart page, it still showed the old SharePoint logo. In SP Designer it did show the correct logo though..
Even after changing the masterpage, the logo would not change..changing it via the admin panel had no effect either.
Then I found this post on the msdn forums: Site Logo Not Changing on Web Part Pages
The solution was to edit the page and delete (or comment out) the TitleBarWebPart..:
Just open the site in SP Designer and search for the “TitleBarWebPart”. Put it in comments, save and open the page in your browser.