Most directories have a shelf life that expires when the domain does
most are sitting on shared servers with 1000's of other dirs
Most have no moderation
Most are spammed to death
The only value I see is bidding for a homepage link on bid directories .. and even then they're only good for PR (which isn't worth much in and of itself). Don't get me wrong, a link is a link, IMO xrumer blasts give you more bang for your buck and that's not saying much.