Without a doubt, I would get your own domain name and setup a WordPress.ORG blog. Not the .com version of WordPress. the .com version. You want your blog on your own hosting so you own the content and control it.
Then have your main blog on your domain and post there regularly.
You can also post related articles on other places like Squidoo, ezine articles, hubpages, etc... and link them back to your main site (WordPress blog). The content on those others sites will all be completely different - but related articles that link back to your main site.
But if you do not have a site at all; I would start with a blog on your domain and work on building quality link-worthy content there; because the best way to get traffic and backlinks to your site is to create content that OTHER people want to link to.
Using Squidoo, hubpages, etc.. should be seen more to drive some traffic than for backlink building.
Definitely use Twitter for traffic & Facebook.