A Backbone.js router subclass that disables the hash fallback mechanism in favour of just navigating to the location (just like a normal link would behave)

router.coffee

class MyApp.Router extends Backbone.Router

  hasPushState: window.history and window.history.pushState

  # Override the navigate function to remove Backbone's #hash fallback for 
  # non-pushState browsers. Instead we just navigate to the new location using
  # window.location
  navigate: (fragment, trigger) ->
    if @hasPushState
      super(arguments...)
    else
      # Backbone navigate paths don't start with a forward slash, so we may
      # need to add one
      fragment = "/#{fragment}" unless fragment.match(/^\//)
      window.location = fragment

  # Navigates to the href property of an event's currentTarget whilst ignoring
  # right clicks, middle clicks, shift-clicks etc.
  #
  # Handy for using from within event handlers:
  #
  #   class MyApp.HeaderView extends Backbone.View
  #     events:
  #       "click a.home": "home"
  #     home: (e) ->
  #       MyApp.router.navigateToLink(e)
  navigateToLink: (e, trigger=true) ->
    if e.which == 2 or e.metaKey or e.ctrlKey or e.shiftKey
      # Make sure we return true in case we're used as the return value for
      # the event handling function
      return true
    else
      # Backbone navigate paths don't start with a forward slash
      @navigate href.replace(/^\//,''), trigger
      e.preventDefault()

router.js

MyApp.Router = Backbone.Router.extend({

  hasPushState: window.history && window.history.pushState,
  
  // Override the navigate function to remove Backbone's #hash fallback for 
  // non-pushState browsers. Instead we just navigate to the new location using
  // window.location
  navigate: function(fragment, trigger) {
    if (this.hasPushState) {
      return Backbone.Router.prototype.navigate(fragment, trigger);
    } else {
      // Backbone navigate paths don't start with a forward slash, so we may
      // need to add one
      if (!fragment.match(/^\//)) fragment = "/" + fragment;
      window.location = fragment;
    }
  },
  
  // Navigates to the href property of an event's currentTarget whilst ignoring
  // right clicks, middle clicks, shift-clicks etc.
  //
  // Handy for using from within event handlers:
  //
  //   MyApp.HeaderView = Backbone.View.extend({
  //     events: {
  //       "click a.home": "home"
  //     },
  //     home: function(e) {
  //       return MyApp.router.navigateToLink(e);
  //     }
  //   })
  navigateToLink: function(e, trigger) {
    if (arguments.length != 2)
      trigger = true;
    if (e.which == 2 || e.metaKey || e.ctrlKey || e.shiftKey) {
      // Make sure we return true in case we're used as the return value for
      // the event handling function
      return true;
    } else {
      // Backbone navigate paths don't start with a forward slash
      this.navigate(href.replace(/^\//,''), trigger);
      e.preventDefault();
    }
  }
});

This gist looks a little outdated. As of 0.9.0, a hashChange: false option for Backbone.history.start() has been added that should accomplish the goal of this gist.

That aside, also as of 0.9.0, the parameters for navigate are (fragment, options) and the lines

      if (!fragment.match(/^\//)) fragment = "/" + fragment;
      window.location = fragment;

don't take into account the root option (pre-0.9.0).