If you are a heave Gmail user like use here at Doztech. Then you will probably like what Google is doing with the Gmail Favicon. Google just enabled a Lab that will give you an Unread message icon. Here is how to enable.
Go to your Gmail account and go to Settings and then Labs. Scroll through until you find the Unread message icon and Enable it.
Go down to the bottom and click Save Changes.
Then enjoy how many emails you ignore with a fancy Favicon. You can also pin the tab so you just have the icon.