I run the same setup as Stephen and have very little problem with spam now, Simple TB Validator stops a lot as most spam is from trackbacks with fake endpoints.

The DYPM helps for a simple human test for comment form spam.

And anything that does gets through gets caught by Akismet, which makes looking for false positives a whole lot more pleasant.

As without the measures I can get a few thousand spam comments a day, and trying to find the real ones…is not easy. Especially with Akismet which doesn’t give you any options for sorting or parsing – e.g show any ‘caught’ comments for the most recent 5 posts and ditch the rest.