Thing is you actually don't need to submit to these at all, just make sure you've submitted to google, yahoo, aol and msn. The rest will cream off information from those.
i understand you might want to submit for a backlink but that's not necessarily a good thing as some include a no-follow or encrypt urls or the big 4 recognise them as link farms.
I'm not saying there aren't a few that are useful, just don't go submitting to hundreds thinking that it'll make any positive difference.