Here's the code I use for my favicons. I'm using FF10 on Windows 7. The favicon.gif I use is a 48x48 image.
<link rel="shortcut icon" type="image/x-icon" href="/images/favicon.gif">
<link rel="icon" type="image/png" href="/images/favicon.gif">
Have you tried it with just the one link tag? If it's the multiple tags that are the issue it should be an easy fix. Also I notice that your type attribute doesn't match the file type.
I believe this was due to the rel tag having two attributes, this should now be fixed in 3888ff9 . It would be great if you could check it out.
Closing as resolved.