TruBar 3.0 (Lessen) is a plugin that asks anonymous users to click on a link before posting a comment or registerering on a weblog.
Downloads Suite lets you manage downloads on your wordpress site. Files can be uploaded and organized into groups, linked to specific pages. Their access can be restricted to registered users with a specific user level. Manages both uploaded files and external resources (link via URL).
Alternate Comments Form allows you to add an extra contact form to your websites.
EasyBan will allow you to ban people from your site temporarily or permanently.
Rank allows you to create a “ranking” system for your regular blog commenters.
7 Social Services Plus is really simple plugin that will add bookmark links of Digg.com Netscape.com Reddit.com Del.icio.us Stumbleupon.com Google.com Socialogs.com and Socialposter.com