Collapsible Categories Widget allows for collapsible category lists in the form of a widget.
DualFeeds turns your feed into two separate feeds (full post and summary), allowing your readers to subscribe the feed of their choice. (Upgraded to v. 1.1)
Duplicate Post allows you to create a draft copy of a current post.
GigPress is a WordPress plugin built specifically for touring bands, allowing them to list shows, tours, Google maps, and more.
Obfuscate makes email addresses in your posts and pages obscure, thereby reducing the chance of your email address getting picked up by a web crawler or bot and used as a spam target.
Trustworthy XHTML lets you control how much auto-formatting WordPress does both while using the Rich Text Editor and after posting articles.