Hi! As I know that when you submit your sites to social bookmarking sites, you don't notice that there are two sections in social bookmarking: upcoming section and published section. Usually, when you submit your site to those social bookmarking, your sites will listed into upcoming section; so it is not counted as backlinks. Here I collected some good social bookmarking sites; you can use those sites for submitting. And also get nice backlinks for your site because those sites approve your links immediately.
http://digg.com
http://mixx.com
http://www.qiel.com
http://yoosubmit.com
http://uselections.com
http://youmob.com
http://kwzz.com
http://yapod.com
http://yoogr.com
http://ibuzzs.com
http://slurke.com
http://woccle.com
If you know more, please share with me. Thanks.