I've been using the JS-Kit widgets for comments and ratings for this blog, and I'm really happy with them. JS-Kit commenting provides very effective ways to fight and delete spam, and I love that people can create avatars for their comments. The star-rating that you see is also from the company.

JS-Kit is installed on 550,000 blogs and has already managed 75 million comments. It powers major sites like eVite, Sun Microsystems, InfoWorld, JetBlug, and Experian. If it can handle icanhascheezburger (click here to see it in action), it can probably handle anything!