I've been considering to focus all my backlinking plan to commenting on high PR dofollow blogs. I've done that for several days and got quite good result (in 2 weeks my web has gained 2nd page for my main keywords, raised from 3rd page last week) .
Firstly, I tried to comment on wordpress platform, but without any clear reason my comment never appears. Some suppose that i've been banned by akismet. And neither can I post comment on commentluv or keywordluv blogs.
I've stumbled across a blog which recommends posting on disqus blog yet I'm quite sceptical about its effectiveness since some people say that the backlinks wont count as google can't read the java script.