In reply to RT Cunningham.

I use Conditional CAPTCHA too and I think it works really well, but the one problem I have with it is that if Akismet doesn't identify a comment as spam, then Conditional CAPTCHA doesn't perform a second check, it just assumes that Akismet is right. So while using Conditional CAPTCHA gives me confidence that all real comments are coming through, I still get spam comments coming through as well sometimes...