aposai

Display your archives in collapsible mode using ajax and jQuery.
Each subnode is loaded via ajax as per user request, so not whole archive is loaded each time your archives page is displayed. If you have performance problems or server issues with other archive plugins, try this one and enjoy.
It also displays the post count for each year and for each month and the comment count for each post. And uses your current wordpress date_format to format the dates.

Ajax Archives

Display your archives in collapsible mode using ajax and jQuery.

scribu

Smart Archives Reloaded allows you to display a list of posts grouped by year and month. It also provides several interesting navigation elements.
Format list:
<ul>
<li>list = a list of posts grouped by month</li>
<li>block = a compact block of links to year and date archive pages</li>
<li>menu = a two-level menu with links to year and date archive pages</li>
<li>both = block + list (<a href="http://scribu.net/archive" rel="nofollow ugc">example</a>)</li>
<li>fancy = menu + list + JavaScript (<a href="http://www.conceptfusion.co.nz/archive" rel="nofollow ugc">example</a>)</li>
</ul>
No support
I do not offer support for this plugin, either free or paid.
Credits:
<ul>
<li><a href="http://justinblanton.com" rel="nofollow ugc">Justin Blanton</a>, for the original <a href="http://justinblanton.com/projects/smartarchives/" rel="nofollow ugc">Smart Archives</a> plugin</li>
<li><a href="http://www.conceptfusion.co.nz/" rel="nofollow ugc">Simon Pritchard</a>, for the fancy format</li>
</ul>
Links: <a href="http://scribu.net/wordpress/smart-archives-reloaded" rel="nofollow ugc">Plugin News</a> | <a href="http://scribu.net" rel="nofollow ugc">Author’s Site</a>

Smart Archives Reloaded

Easily display posts grouped by year and month, in one or more elegant formats

Ajax Archives vs Smart Archives Reloaded