Digg can be a horrible waste of time. With the constantly updating links to interesting things around the web, you can lose many hours hoping from site to site. On the other hand Digg can be a great way to make sure you don’t miss something important. For example, I learned that Gmail had added IMAP access from a Digg post.
What I have found to work well is checking Digg once a week or once every month. Choose the technology category and then view the top items for the last 7 days (or last 30 days). (If you do this with the front page category, you’ll be sifting a bunch of photos and videos.)