While we're waiting for the Nautilus sidebar to categorize items displayed with headings, we can make the sidebar a little more beautiful by changing a little code ourselves.
On the Ubuntu forum is a how-to guide that allows you to change the icon size in the Places sidebar in Nautilus filemanager. See modified Nautilus screenshot below:
It requires getting a bit technical and it will take some time. You should be able to uninstall this simply by reinstalling nautilus package with Synaptic, but use it at your own risk! The original how-to guide was written for Feisty Fawn(in 2005), but a single step can be altered for Interpid Ibex.
Read the whole thread here...