I don't think you can really say 1 of them is the best because you will always need a variety of links.
I choose other. In my opinion, nothing beats PAD. Find quality, authority domains in your niche and ask them to publish on of your articles on their sites with a link to your site. Beats these 1000 links you get from unrelated crappy websites.
I think social bookmarking is the fast and accurate method of backlinks for individual pages or sub-pages. But if someone wants to get back-links for the main domain then blog directory is the best.. Article submission is best for both, but counting very slow coz it takes time to approval for publishing articles
If you working on a new site, you can starte with all of them except link building. Once you have established a good base for it, I think link development means all
Its the time for Article submission . buy some article posting softwares i like article post robot and then post them manually or automatically as you like and you can post 100 article in 1 hour easily trust me
None of them are good; you forgot the most trusted links. Merit based links (as in editorial links) which are in the content should be on the poll.