This comprehensive list of Digg tools received 1550+ diggs within 48 hours after it was submitted (http://www.digg.com/links/Digg_Tools_2). Note that the list is much longer than what I clipped. Weston Campbell also offers a Digg sidebar for Firefox.
Compare with Pchere's list at http://www.quickonlinetips.com/archives/2005/09/complete-digg-tools-collection/. Both pages are kept current.