This poll is flawed, because you are mixing two different things: "Source of Rules" and "Rules Interpretations". "Sources of Rules" say what the rules are. "Rules Interpretations" decide how to apply those rules to the current situation, which may be a mix of rules from multiple Sources.
The answer also depends on who is making the decision as to what is right. People in the Organized Play games have no choice: the latest published version of a rule is the binding one.
By their nature, the Core Rulebooks are the primary "Source of Rules". On any given topic, whatever the Core Books say is the "Primary Rule".
Any other book by WotC (or anyone else) is a variant, and serves as the "Source of Rules" for that variant. If I choose to use the "Armor as Damage Reduction" variant from Unearthed Arcana (as an example), I cannot expect the Core Books to tell me anything about it. It is, specifically, a REPLACEMENT set of rules.
Errata is a collection of corrections to the book it is matched to. It is not a change in the rule, it is an admission "The rule was supposed to say this but it did not get fixed before going to press; the version in the book is WRONG and this is the RIGHT text".
When it comes to Rule Sources, the book where the Rule was published is "THE Source". Errata corrects the Source, and supercedes it. Later versions of the same Rule need to be evaluated for human error. For example, Complete Divine copied the 3.0 text of many spells and feats from Defenders of the Faith, then published it without being updated. Some of these HAD BEEN updated in the Book of Exalted Deeds. Because of the "Last published is currently correct", the changes were "rolled back" as far as WotC and Organized Play were concerned.
The FAQ and Sage Advice are "Rules Interpretations" (generally). They explain which rules The Sage feels supercede each other in cases where it is not immediately clear. The answers also give The Sage's OPINION on odd situations or specific potential abuses that crop up because of the order in which things were published. I am thankful that Andy Collins, the current Sage, takes more care to be clear about when he makes a "my opinion" or "my approach" ruling than Skip Williams used to.
Hypersmurf's answers are generally extremely good because he is very good at finding the citations to back them up, and at exposing the logical holes in some combinations. Generally, Hypersmurf's ability is the ability to find the most appropriate citation from a "Source of Rules".
And, finally, to answer the original question, there is NO Source or Interpretation that I let stand if I do not agree with it, though I give most things where I am not certain it is wrong the benefit of the doubt.