GoogleSystem has created a really useful widget for Blogspot bloggers, similar to the Wordpress Top Commentators plugin.

Introducing, the Google Blogger (Blogspot) Top Commentators Plugin!

Utilizing Yahoo! Pipes, it sorts the information stored in your comment RSS feed, and parses out the users who have posted the most comments on your blog. There is also options to filter your own name from the list, which you will probably want to do, and you can set the widget to display however many top commentators you want!

I kind of wish I tried it out a little more before I migrated to Wordpress, but it’s still a worthwhile mention, I hope you folks can use it.