*** LowComDom's Online Dictionary: A lot of words, and a good layout. This site's only fault is incredibly slow to load because it uses a graphic for each letter. However, once those graphics load this is one of the best online dictionaries, I've found.
*** The Revised Dictionary: Almost 500 alternate meanings for everyday words. This dictionary invites you to submit your own words and can be used by speech writers to punch up their work.
** 1/2 Quinn's Devious Dictionary: There are tons of revised definitions. My biggest problem with the site is I find no real way to read past the As. I think for that you have to buy the book. And since these are mostly definitions from famous authors, most of the info here is in the public domain.
** 1/2 The Cynic's Dictionary: A nicely laid out dictionary with carefully chosen words. True there could be more entries, but what has been chosen are gems.
** 1/2 The Love Dictionary: Another dictionary that doesn't select a lot of words with new meanings. Still, the ones that have been selected are gems. Nice, readble layout too.