I just wrote an article for those who want to know some of the pros and cons of being listed in the yahoo directory. Feel free to leave a comment on the site or in this thread. You can view the article here: Yahoo Directory - Does it help? Enjoy.
Yahoo directory listing is not 'very' important I would say. But if you are investing big in the link development of a project, it doesn't hurt getting listed on a decent authority web directory like Yahoo! and others. For small time webmasters its a waste of funds. For a company, big investment project as mentioned above worth the listing fee.
like humn said, its the big difference between small website which is not a business and doesn't invest a lot, to a big corporation that set new goals for the future (marketing, etc) you also know that the directory will be there for a long time and wont be panelized or something, i think it's the ultimate investment, its inner pages are well linked and has decent strength you mentioned about the anchor text i see in the article, i think any decent directory will have proper anchor texts, i think when it comes to a directory like yahoo, it would be wise to have non-seo anchor text, google will like that.