I guess tomorrow I am going to go grab some no follow links . . . never really thought about it like this.
Any link that brings in traffic to your site has value. If you're worried about seo then it's not something you want to concentrate on. I will always a take nofollow link then no link at all.
I have a site that I've managed to get onto a couple of pages in Wikipedia and its been there for months. These links are definitely, without any doubt in my External Links on Google Webmaster Tools. And we all know Wikipedia's links are nofollow..........work that one out?
Oh, also just had another look through my backlinks on Google and I have some Yahoo Answer links in there too. Again these are nofollow.