100% correct and great advice, and vary your anchor text a lot. Directories are great for getting some long tail keywords linking to you.
Legit directories and proper anchors will do you wonders. Like anything else you follow a good seo plan, diversify engines you optimize for and you'll do wonders. Keep an eye on googles changes, they are always changing what they find to be OK methods. Latest to hit the ax I hear are social bookmarks, which doesn't hurt my feelings anyways. But lets make this clear if you use any method as part of a robust marketing plan, if something changes you wont see much effect in loss of placement.