Follow or nofollow for SEO purposes

Hi, I would like your opinions of this debate of follow or nofollow for links in webwiz forums. I am currently running my forum and have closed it to new members due to abuse with spam links. I am currently running the forum for reviews and link to many other topics from different topics. I am currently running in nofollow, but because i'm linking to so many other topics from a certain topic would it be better if I used follow?

Thanks, Paul.