Nautilus 3.5.4 has been uploaded to the Ubuntu 12.10 Quantal Quetzal repositories today, bringing some very important changes like a new GNOME 3 style toolbar, new "gear" menu, symbolic monochrome icons for the sidebar and others.
New toolbar / pathbar and "gear" menu:
Don't judge the looks yet, as Ambiance theme doesn't support the new Nautilus yet. Here's how it looks using Adwaita, the default GNOME 3 theme:
full post here