I found two really great firefox extensions today

One is PageAddict and second one is Aging Tabs

I am currently using them & I am finding them extremely useful

Aging Tabs Firefox extension keeps an eye on your open Firefox tabs, highlighting your active tab and fading the aging tags that you haven't used in a while.

PageAddict is a Firefox extension that will help you monitor your Internet addiction. Once you install it, revisit this page (pageaddict.com) to see a summary of the time you've wasted on each web site. You can categorize different sites and restrict how