It really was only a matter of time until ReCaptcha was cracked.
I've noticed an increase in spam in the last week or so. I'm not using ReCaptcha at the moment (because Google bought them out), I was using a similar "code" antispam mod.
I now do the Q&A and that seems to have helped immensely. I put a question or two in there and it rotates between them, which is great.
I think ultimately a solution similar to how Askimet works on blocking comment spam in WordPress would be ideal. I guess StopForumSpam is supposed to work in a similar fashion. Having one authority that manages spam registrations all over the web in theory should be accurate and help. Between a solution like that and a Q&A question, that should cover 99.99% of spam sign-ups.