Are you a dedicated Digg user? If you are, you should give the Digg Toolbar for Firefox a go. It is an easy, efficient way of managing your Digg notification from within Firefox, making sure you don't miss out on any notifications of Diggs that you'll like.
The Digg Toolbar itself is mercifully subtle and non-invasive. The options toggle is on the far left of the bar, the pause function on the right, and another notification toggle on the bottom right. When you install the Digg Toolbar you are asked to chose your notification preferences, selecting the topics you are interested in from a long list of options. You can of course change your preferences at a later date, as well as modifying other settings, such as notification style and whether or not you want to see your friends' activity.
Reading Diggs remains the same, and if you click through on any Digg link while logged in, the page you open will have the usual toolbar across the top. If you want to Digg a previously un-Dugg item, you can hit "submit" from the Digg Toolbar for Firefox, but you'll still have to do it via the Digg website, so in this respect, the Digg Toolbar for Firefox doesn't really add to the experience. That said, it makes Digg notifications, easy to control and monitor and helps dedicated Digg users feel that their experience is more centralized.
Frequent Digg users will appreciate the Digg Toolbar for Firefox's handy notification features, but lament the lack of a direct Digg function.