Dofollow blogs are overrated. If you're searching around for dofollow blogs, you're wasting your time. The best way to connect with bloggers is to network with bloggers in your area. If you aren't sincerely interested in a blog, don't read it. There are enough blogs out there that you should be able to locate strictly blogs that you are highly interested in. Then, read them, and when inspired, post a relevant comment. This more natural way of interacting with bloggers will get you a lot farther than posting comments with the intention of creating links or traffic to your sites ever will. In the end, you'll get more links, and more traffic. What's better than posting a comment with a dofollow link to your site? Having the blogger themselves write about your site and link to it directly. This is just as likely to happen on nofollow blogs. So, really, you would do best to totally ignore the nofollow or dofollow attribute when deciding which blogs to follow. Good luck!
I like to use some of the lists that people pass around. The majority of the sites don't work, but you will find some good ones in there.