NoFollow links only don't give you PR, but for the rest they are as important as dofollow backlinks! Maybe more important, because google knows (almost) everyone is focussing on PR, so they don't want nofollow backlinks. Maybe google gave the nofollow backlinks therefore higher priority ?!?
Compare with dofollow link, nofollow will not give that much weight for your site on google ranking calculations. but nofollow links also have the capability of providing more traffic.
There is a consensus that no-follow links do have some link juice passed, but obviously not as high as do-follow links