My Experiences on Backlinking

I've been testing different backlinking techniques over the past year. Here's what I've concluded:

Sig links - can work, but these aren't good for the long term. You miss a couple days of backlinking w/ sig links, and your site(s) will drop in the SERPs.

Directories - Forget them...need I say more

Article Submission - You can get referral traffic from these sites like EZA or GoArticles - and yeah - sure, they will appear in your backlink list - however, I don't think they can move you up a lot from what I've seen. but there were times when I would have an article from GoArticles and EZA along with my site on the first page...totally dominating my niche. The CTR from with these articles and from what I've experienced is pretty low - and I've had some very well written articles.
However, I think if you get enough articles that are unique and well written, this might be the best approach???

Social BookMarking Sites - A few sites like Digg and Reditt can bring you referal traffic. I've noticed that Digg can get indexed in less than 24 hours but then will drop in the SERPs over time. Overall, I didn't see Social BM sites help my sites in the SERPs. And G has to know about them and dismisses them as spam since a lot of ppl do bookmarking in order to gain one way links. I think G is much smarter than that and knows that a lot of these links in these type of sites are not natural.

Press Release Sites - I'll be tring this next week - so I guess I'll see for myself.

Profile linkes (or as some ppl would like to refer them as "Angela's Links" ) - I don't bother with them...

Web 2.0 properties such as Squidoo and Hubpages - I really don't think they can push your site up that much but again, will get some referral traffic.

As far as online opimization - for my own personal sites (and not really my clients), I focus on material that I have a passion for. I write lots of pages and make sure they are well optimized (sometimes usually for long tailed KWs) and have been seeing results from that. If you were to pick one or the other, I would think that online is really more important than offline/backlinking. Seems that G rewards you if you have a lot of material that is unique.

Conclusion - Spend more time optimizing your site than backlinking. For me, I think I have gotten further with writing more interesting pages than try to backlink the heck out of my site(s). This is my own opinion - what have been your experiences?