I don't think this is something that can be crowdsourced. The arguments here rest on authority (and in this case, it's well justified). You want the opinion of someone who has surveyed the field and has studied further than the respective textbooks take you. There may be some authorities whose replies are worth listening to, but these are difficult to distinguish.

For instance, a user recommending CLRS over TAOCP is an odd piece of advice, since TAOCP is distinctly not a textbook. The user purports to have read TAOCP, an assertion with a low prior-probability.

Unfortunately, I do not think we can rely on the advice of anonymous internet contributors. With no way to enforce the rules, LessWrong fails to do due diligence and is merely spreading the opinions of those that reply.

So, to remedy that, I would add a 4th rule: You must state where your authority on the subject, and on the choice of textbooks comes from.