I don't have much to say about formal logic in these recommendations. Critical thinking and argumentation don't require much background in formal logic. A basic understanding of logical concepts and a small handful of common argument forms is more than enough.
But it is a fascinating subject, and I know that many people who come to the Academy site are students in logic classes, looking for some help in understanding the material they're being taught.
It's also a subject that has deep ties to mathematics and computer science, and one that has played a central role in the intellectual history of the West.
I have a lot of logic texts on my shelves. The ones listed below are mostly just an excuse to offer a few comments.