Is it was still worth paying the $299 fee for a Yahoo! listing?
IMHO there is no yes/no answer to it. It would depend very much on the nature of the site, the value of a 'sell' (if the site does sell stuff), the time pressure to generate visitors and such like. In fact - it is certainly related to your budget If that sum of money was not a significant part of the marketing budget, I see no harm in paying for one year. Then, the results should speak for themselves and indicate if it is worth paying for a renewal or not.
Having said that, I suspect that the sum involved is NOT inconsiderable, otherwise you probably wouldn't have bothered asking the question in the first place. If so, I think that you sould at least consider the other directories, some of which were mentioned already. Another directory, Gimpsy, will consider your application within 72 hours and promote your site (if approved) for 90 days, all for the one-off fee of less than 10% of Yahoo's annual charge Moreover - you can even save that money and submit for free, but then the review will take significantly longer.
Hope that helps!