Here are a few WordPress plugins I have been really happy with lately:
Admin Bar Minimiser
Minimizes (and brings back) the WordPress admin bar at the click of a button, very nice…
Awesome Flickr Gallery
Creates a photo gallery of your Flickr photos with many customization options, uses the Flickr API… powers the sidebar widget here.
Dynamic To Top
Very nice with lots of options, JQuery-powered… at lower right on these pages.
Plugin Organizer
Selectively disable plugins on any post! (And many other powerful features.)