Ok, for starters, I have never done recips... not for a few years at least. That dog was beaten down a while ago...
As for directories, that is part of what is considered foundational link building ( as is article directory subs). While not as valuable, it can be done with effect by hitting the higher quality locales.... so it can still be part of a link building campaign.
Forum sigs (and blog commenting) is also not a major player... if you're on a related forum/blog... great, drop them; but it isn't a seek and destroy tactic... merely coincidental.
I would also consider some competitive analysis... look at your core target terms and the top sites in the SERPs to see where they have gotten links from. This always gives some great ideas... once again, only the higher quality opportunities.
Beyond that, it depends on the market, business model (website type) and more as far as what one should do when developing a link building campaign.
I also like to occasionally look at the various methods of link baiting for new ideas... I had a post a while back on
Link bait ideas and have a bunch of links to
link building tools and resources which also might come in handy (all free tools etc..)
Social media marketing programs are often good for finding links (exposure) that you may not find elsewhere... but I would get a better idea of how to run one first... doing SMM as a standalone link building tactic, is not a good idea....
..but once again, each situation will differ.
BTW, I am almost finished my '
SEO Handbook; Link builders edition' if you PM me I shall put you on my list of peeps getting advanced copies (free of course...)