clean

Add This - The popular social bookmarking button is available for Blogger accounts.

Easy Comments - This widget allows you to add commenting to any page of your site by placing the widget at the bottom of a page.  Allows people to say if they liked the comment, includes comment threading and more.

Google Search - Add an AJAX powered Google search box to your blog that you can allow to search the web and your blog, or even just restrict it to the contents of your site.

 

Popular Posts - This widget will take a look at your comments, up to the last 5,000, and generate a list of which posts had the most conversation around them.

Recent Comments - Display the most recent comments on your blog in this widget so that readers can join in the conversation.

Related Posts - Not so much a widget as a hack, this will give you the related post functionality that so many WordPress powered blogs use.

ShareThis - The highly customizable