EZDigg
If you haven't been to digg.com before, you really should stop by. It's a constant stream of really cool technology-related news rated by real people. So really cool stuff hits the front page and really lame stuff doesn't get in your way.
I'm a relative newbie to the digg.com world, but I have submitted a number of stories and I realized that I'm quite used to my "post to del.icio.us" toolbar buttons for del.icio.us but I couldn't find the same thing for digg.com. I'm not saying it doesn't already exist, but I couldn't find it quickly, so I built it.
If you submit stories to digg.com even once in a while, try my EZDigg This! toolbar button for Firefox, Internet Explorer and Opera. You can see how to set it up at this page.