Allows you to group your archives by month and years with several customization options.
WARNING: This plugin is no longer being supported by its developer and may not work with future versions of WordPress. A replacement by the same developer is available called PW_Archives. It's faster, more efficient, and implements the latest WordPress security features.
This plugin makes the posts in your nav easily-groupable by month and year. It gives you quite a few easy-to-implement options that allow you to customize both which date groups are listed as well as how the markup is structured.
Perhaps the primary benefit of this particular plugin over other plugins that do similar things is its ability to enclose the post count within the anchor tag. This solves countless problems for anyone using the CSS style display: block on anchor tags, which produces the undesirable result of forcing the post count down to the next line.