One of the best ways to browse, for security and privacy, is to us the VMware Player.
http://www.vmware.com/products/player/
It is free. There are pre-made images (several OS choices) up that are pretty much just an OS and a browser. You can set the image so that any changes made to the virtual hard drive (which would mean cookies, temporary files, virii etc) will not persist. So next time you start it up, it is fresh.