I just installed Disqus, a commenting system that allows readers to comment using a guest, Facebook, Twitter, Yahoo, or OpenID account, on my WordPress (.org) blog.
I like how you aren’t forced to use a Facebook or Google account to comment.

Edit: Never mind. To simplify things, I’m going with WordPress’s commenting system. For now. 12/27/12
Testing Disqus with Twitter.
Testing Disqus with Twitter.
Testing Disqus with Google Apps account.
Testing Disqus with “Guest” account.
Testing Disqus with Google account.
Testing with “Guest” account.
Testing Disqus with Facebook.
Testing Disqus with Facebook.