In the comments to Enthusiast and Fanatic Badge on the blog, a comment was added that a nice feature would be adding the number of consecutive days you've visited to the site to the user's profile.
I’d love to see on your user page a count of how many consecutive days you have been on SO/SF. Kind of like looking at your uptime on a Unix box. - Code Slave
I believe it would be a good feature and wanted to put it out there for discussion.
I know personally, I would like to be able to track how many consecutive days I've visited the site without having to figure it out on my own.