Both activities are important for your website for increasing good ranking. But matter is that your submission are good in quality like submissions are done in High Pr sites, appropriate category choosen in Directories etc.
Both are very useful for SEO Experts but directory is mainly for backlinking nothing else while bookmarking is for traffic.bookmarking is very useful if is done on good pr sites.
Both are off page activities & both are useful for your website. But matter is that your all submissions in DRS as well as Bookmarking are quality Wise.
Both are beneficial for your website promotion. Both are getting backlinks to your website. But matter is that your submissions in both activities are quality wise like submissions in good PR sites & Fast approval sites.
Like many others have said both are good for your site but i would say quality links are more important over the quantity of links you get i would also say social networks are maybe better if they are better quality links because directories can often times have a negative effect on your sites i have heard many different reasons for why this could be but i cant really pinpoint it myself yet.
directory and social book marking both are important for any website Directory submission gives your website good position for much longer time then social bookmarking.directory submission is best way in all off page seo techniques . you can get good backlinks from diffrent domains. its gives your ranking a stability. Social bookmarking i salso a good off page seo techniques in which you can get good ranking position but for shorter time may be for some days...and then your keywords cometo their old place. it can not fix them for some time like directory submission but its also useful to get good traffic and quick ranking if you do with directory submission and other techniques.
Just keep it going every day, and things will be going up few months later, social bookmarking is good way, but you need to build a huge connections on each social bkmarking site so people could find you.