According to Off site/page SEO, can you order by high priority to improve your SERP 1. Article submission 2. Press Release 3. Do follow blog replay 4. Forum and yahoo replay 5. Directory submission 6. Social Bookmarking 7. Classifieds submission
All of them are same but personally I prefer forum posting, social bookmarking and article submission, not only for seo but also generate targeted traffic to my website
Press releases (and, generally, public relations) has the biggest potential to leverage your efforts. Also, it builds the most natural link profile possible. As for the poll, it's a bit misleading. It's not about the techniques (each technique can yield good results). It's about how you use them. More specifically, it's about the quality of the links you build. Each technique has the potential to get a good link. And, any good link is worth more than 100's poor links, no matter what technique is used.
Article Submission and Press Release are of the same levels for me (top priority), then social bookmarking follows. The rest of the link types, I randomly create/use for online promotions