Pngfix: fixes problems with transparent png images in Internet Explorer 5 and 6
GATracker: allows you to load the google analytics tracker very simply at the beginning of the page. Also allows for tracking of internal links such as pdfs.
AddThis: adds social bookmarking links to your website.
BeautyTips: Nice looking and flexible tooltips
ed. 6/1/2009 - added AddThis
ed. 6/12/2009 - added BeautyTips