Highlight Comments allows you to highlight comments, which are worth reading. It can highlight your own comments as well and is fully customizable.
If you want to show your readers which comments on a specific post are worth reading, just click on a 'highlight'-link below them and they will be highlighted automatically (uses custom-fields). This plug-in also adds functionality to highlight your own comments, e.g. the blog author.
Additionally, Highlight Comments will create a list of noteworthy comments and put it below your post. It would then look like this:
There are currently 2 comments highlighted: [comment-id], [comment-id]. If you wish, you can even change this text.
Eventually, you can set-up your Cascading-Style-Sheets that will be used to highlight comments via the administrator-GUI of WordPress.
You can deactivate and activate every feature separately.