Relentless spammers

I made an elgg site (version 1.8) a couple months ago, and it didn't have a problem with spammers until just the last couple of weeks.

I proceeded to install the following plugins:

gutwacaptcha :

Spam login filter with all the defaults:

and Honeypot spam catcher:


They still got through at about the same rate as before, which I suppose means that the captcha is useless, they're using domains/IPs that aren't on the blacklists, and they know to look past that hidden honeypot field that is supposed to catch them.

What to do now? Before I mess around with the code in these plugins, I'd like to know if there are any other measures you guys have used to prevent the onslaught of spam accounts being created just to post a single spam post.

On a side note, I noticed that every one of the spammers was creating an account through an email, and as a temporary fix, I blacklisted emails, but of course, they're now starting to come in with yahoo and hotmail, and so the bad workaround is an even worse one.