As far as CAPTCHA’s go, I think that the one that Digg.com uses for story submissions is fairly reasonable. It’s monochrome, decent contrast, and doesn’t try and get too fancy with out of focus characters or exotic fonts. Of course I have a preference for my own PuzzCAPTCHA as far as usability goes, but for mainstream CAPTCHA’s I think Digg’s in intelligently done.
Maybe a little too intelligently, actually. I think that it might be trying to send me messages. I logged in to submit