Most effective form of CAPTCHA?

Question

Of all the forms of CAPTCHA available, which one is the \"least crackable\" while remaining fairly human readable?

Answer 1

This information is hard to really know because I believe a CAPTCHA gets broken long before anybody knows about it. There is economic incentive for those that break them to keep it quiet.

I used to work with a guy whose job revolved mostly around breaking CAPTCHA's and I can tell you the one giving them fits currently is reCAPTCHA.

Now, does that mean it will forever, call me skeptical.