I see many links to my sites from free directories in google.com/webmasters. Honestly, most of my links come from free directories .
Well, I think it's time for some testing then - submit to 100 directories, check back in 30 days, see your %s of backlinks
Hey, Just to add my thoughts, I've noticed a real shift in googles backlink acceptance criteria in the last couple of months. Like most I was using free directory submission services, But i've not seen any of these appearing in my backlink profiles, when normally within a few weeks they would start to appear. Google are getting increasingly clever at sorting out the wheat from the chaff it would appear. Quality is the only way to go I think for the future.