Which Backlinks Actually Work Discussion

So after ranking 5 websites with about 40 individual pages from those sites ranking on page #1 for a keyword or multiple keywords ive come to only one definite conclusion in regards to backlinks. The only backlinks ive ever built that I can say with absolutely certainty definitely helped my rankings were profile signature and bio links. Now im not saying that the others didn't help im just saying I can't be certain.

Everytime I do a profile link blast I see some change. With new sites they'll usually dance like crazy and with old sites within a day or two i'll start seeing some movement. In regards to web 2.0, article directories, blog comments, article distribution networks, ive done it all, im pretty certain they had to have helped but im never sure.

If I take a brand new site and throw 2000 blog comments it may not move, it may drop, it may stay still. If I do a big Web 2.0 blast it may not move, it may drop, it may stay still. Same with article directories ect... Profile links always spark movement sometimes temporarily bad but in the end good.

My question to you all is what have your findings been. Aside from actually having visitors build your links naturally or emailing the webmaster of a high PR site and asking for a link. What of the typical link building methods have people seen work first hand.