Great question Jon. I hope you get some good answers.
Frankly, I haven't found any tool truly that great in building them. In terms of researching them, the ones you've listed above are great for the most part.
I try to just keep up as much as possible on all the top webminars and posts about link building to find the best "strategies" and solutions for link building. Unfortunately, I don't find any tool to be truly that good in building links. I just spent 6 hours today building local directory links for a client like the yelps of the world so they have not only have more backlinks, but also have more sources of traffic.
Frankly, one of the "best" tools has been finding great vendors IMHO. And when you find a great vendor who can build them for you, you've literally got the best tool of them all - labor who will do it for you. Wish I could share all my great vendors here, but unfortunately, it took us years to find them. 
