iRotater Directory is free now and wil stay free for atleast two years. but ocassionally I will turn on payments to stop spam
http://top10s.net/directory/ http://ziperion.com/ http://best10s.com/ All these 3 ranks around 50k-500k in the ALEXA submit it and fast aproval
Thats exactly what I do, when i'm gettign spammed lots I just switch it to paid for 24 hours till I can clean things up a bit. My Free Directory will be set to paid for the next 18 hours or so then it will be free again.
http://www.wezp.com it is free and has a good design. you can check your sites' stats. (Backlink-alexa rank-Live Pagerank-indexed Page etc..)
Of course the only directory that accept parked domains and websites for selling too, this FREE directory + FREE auctions site owns!