If you just can't get enough of Facebook then the Facebook Toolbar for Firefox is a free extension that gives you enhanced access to Facebook from Firefox.
Facebook Toolbar sits quietly at the top of your browser and provides twelve essential shortcuts to different sections of Facebook i.e. profile, friends, photos and groups. It also features several icons to show you how many friend requests you have, messages you've received and invitations to events and groups.
One of the handiest features of Facebook Toolbar is an alert system similar to an IM client that tells you if there has been any activity on your profile since you last logged on. The problem with this, if you've got lots of friends, is that it's constantly alerting you and can be a real distraction while you are working. You can even have a sidebar of your friends faces staring at you as you work although that's taking it a bit far in my book.
Facebook Toolbar a seriously addictive toolbar that can easily distract you from your work but if you can't get enough Facebook in your life, then you'll love it.