From the following Submissions which gives highest weightage?Which is best method for getting backlinks?
Forum posting / Directory submission / Article submission /Blog Posting.

Just wanted an opinion.

the first one and the last aren't "submissions" it is SPAMMING blogs and forums.

and who knows or cares for that matter.

any or all of them could be equally crap or equally useful, site A could be more useless than site B and site C could be marginally better than site A.

And if you think that SEM/SEO is "do A,B & C and X will be the result" YOU'RE IN THE WRONG BUSINESS!!

Oh and BTW

links are NOTHING to do with "optimising"

In my opinion, the order would be like this
1. Forum
2. Directory
3. blog
4. Article Submission

Reason, Forums would be the most appropriate back link compared to other suggested tactics. Also, Blog should placed 2nd in the order but blogs would take more time duration to provide us a link back. Therefore, I suggest the above stated order would be more recommended.

I don't really think that there is actually a best method in getting backlinks, getting them backlinks doesn't just rely on those techniques because those can either help you, harm you and just waste your time... the best thing to do with these techniques is not to weigh which one would be the best but to study those techniques and the sites that those techniques are related to before actually performing them...

In my experience article submission is one of the more effective link building strategies.

Forum posting generally takes more time than it is worth, unless the forum is related to what you are promoting. Then the potential for direct traffic can make up for the time spent.

Blog commenting can be a good strategy but it can be tough to find good dofollow blogs that aren't full of spammers.

Directory submissions are no longer as beneficial as they once were. Google now gives less weight to links from many directories. There are less than 10 directories that actually help much and most of those are paid directories.

The best strategy is to diversify your link building techniques. Don't just rely on any one technique as you never know which technique Google is going to fight back against.

I will say Article and Blogging will be in top as it is both related to fresh content.

^well, posting in forums could also be a way of posting fresh contents wouldn't it? but considering that they are more considered to be advertising than to get links... I guess ^ is good as well.

posting in forums could also be a way of posting fresh contents wouldn't it?

Only for the forum

In addition to that list.. I guess "social bookmarking" gives the highest weightage... others also prefer using that kind of strategy