New trend alert! There are a number of new sites and services to help you make the most productive use of your time. I've had great success using To Visit, Or Not, so I'm happy these services are becoming so popular. The latest: PageAddict, a Firefox plugin that tracks your web browsing history and turns it into a helpful info graphic. Once you install the plugin, it quietly monitors your browsing habits, allowing you to access your history at any time. Apply tags to sites (work, email, time-wasting) to see exactly how you're spending your time.
Even more helpful, if you find yourself spending too much time on a particular site or category of sites, you can set the plugin to restrict your usage. Use a certain tag ("time-wasting," for example) to designate sites you want to restrict, and select the "restrict" option for that tag. View your history in graph or percentage format over a period of time and figure out exactly which sites are becoming giant timesucks.