There's been a LOT of discussion here about free and paid directories and how they are valued by the SEs, so I thought you may want to watch this.
http://www.youtube.com/watch?v=1Pu1YWcIh04
I don't submit to directories anymore (except for Yahoo) for the reasons Matt mentions here. This video confirmed what I've thought all along and I have no regrets about paying for a Yahoo directory listing. It definitely carries weight, so if you can afford it, it may be worth it for a quality backlink. For the record, I only paid the $300
ONE TIME (not recurring) for all my sites because they fell into a non-commercial category.
Of course you can get traffic without a Yahoo directory listing so don't stress out if you cannot afford it. And I totally understand why some people think it's not needed. You can get into Google without it. My point is that Matt clearly stated that this directory has more value than all these fly-by-night PageRank 7 directories that spring up everywhere.
Take home point: Before you submit to a directory, check to see if they accept anyone and everyone who submits (is there any editorial control?) and are they providing a certain value that other directories don't? If they just accept anyone who submits (free or paid) then Google
may devalue that directory.