Google Toolbar Button Plugin: The Google Toolbar Button plugin gives you a link in your sidebar (or wherever you want it in your theme) that installs a button to the google toolbar. The button give the ability to monitor the RSS feed of your blog from the Google Toolbar. It also adds your blog to the list of possible places to search when running a search from the Google Toolbar.
WinLiveStatus is a plugin that lets you show your Windows Live Messenger status in you blog sidebar. WinLiveStatus is XHTML valid and includes 7 status images and 1 error image incase the bot decides to go moo.
Top Cat lets you assign the main category for a post when you select more than one category for it.
vlowe YouTube Gallery displays a users videos and favourites as a gallery with player. Including video information and comments.
Nice tooltip for links with href- or title-attribut on the complete website or one ID. You can change between two nice tooltips – Bubble Tooltip or Sweet Title.