There's a list circulating around the writing neighborhood of the blogosphere lately, a list called The Twenty Worst Agents. I found it at All Kinds of Writing, but apparently, it's also on many other blogs and/or sites.
Seems this list riled some tempers and sparked a bit of controversy, and the threats and legal mumbo-jumbo even cost Absolute Write their hosting (they've moved and are presently transitioning to their new server.)
Funny thing about controversy though, it draws more attention and, for me anyway, makes me more likely to believe the list is completely legitimate (I've seen the lists compiled by miffed writers and offended poets, know what I'm saying?) So, I'm posting a link to the list, where you can also find more links to people who've posted the list.