Please before anyone shoots me down, I am not saying 'do follow' links are bad. On the contrary I think if you can get a highly relevant do follow link to your site from a high PR site, Yippee.
But lets face it, How often does this happen? A lot of the 'do follow' lists are PR 3 at the most sites which I suppose are okay for the link, or are they?
Let's take a closer look.
These sites with 'do follow' links tend to attract hordes of webmasters all seeking the PR boost that a link from these pages can give to their sites. So you end up with a not so significant blog post with over a hundred comments.
But hey, do we not know that the more links there are pointing out of a webpage, the less PR value each link has?? Hmmm
So I say forget about whether the links are 'do follow' or 'no follow'.
Just post quality content on sites that are not overrun with comments.
A high traffic, 'no follow' blog, which is not over-run with comments, on which you can add something useful to the conversation is probably going to get you more traffic, from human visitors clicking on your link, than a post that is comment 125 on some 'do follow' site