If you wish to (try) to cut on the Browsing related procrastination you should take a look into PageAddict, this little gem does the following:
- Track the amount of time you spend actively using Firefox (duh!);
- Allows you to create different groups and tag the sites you visit (so you can see where you are wasting most of your time);
- Allows you to setup a daily time limit for each group individually or more extreme just block them;
- Easily blocks (like said above) sites without having you mess with .hosts file;
- Generates History Report and Graph so you can see how much time you are wasting (see below)
- Its free, easy to use and pretty useful;
I will be recommending over time, other programs that a long with PageAddict, can help you control and monitor the amount of time you spend on your computer.
Some screenshots:
Give it a shot and if you dont mind let me know what you think of it 
Cheers
