I'd rather have posts over members anyday, and we get more new members registering than new posts! That means that not only does every new member not make at least one post, but the number of existing members we have visiting and supposedly posting doesn't even make up for it.
I got my first dosage of pharmacy spammers, and they came from an email address with the .ru prefix.
This made me ask, what email addresses should I ban from registering?
I dont want to get to deep with banning things like GMail and Hotmail
It's not what you are asking, but I've cut most of my spam traffic by banning one single ISP in Moscow: mtu-net.ru. I have no explanation why this particular ISP sent me all spammers, but this worked out very well for me. You may give it a try if you don't expect users from Moscow on your website.