I finally got around to writing a port of an amazing Firefox extension to the Chrome browser. MileWideBack (available on the Mozilla site) turns the left edge of the browser into one large back button, so when the browser is maximised (as it normally is for me at least), you can just slam the mouse onto the screen of the screen and just click to navigate.
By default, its left-click goes back, right click goes forward, and middle click to close. Also using the scroll wheel on the edge of the screen cycles through the tabs. There is an options page so those without middle mouse buttons can set up the extension differently.
Its now available on the Google Chrome extensions site: get it now!