Some discussion has opened up in the comments regarding my post about reading the suttas. It occurred to me that I haven't made the most imortant and salient point; the reason to read the suttas is to hear the most undiluted Dhamma directly from the most qualified source.
Who was the Buddha anyway? If you take a traditional view, as I do, he wasn't just some really smart guy. On the other hand, he wasn't a deity or incarnation of one either. He was an extremely rare historical occurence of a fully awakened human being. By his own effort, he completely purified his psyche and penetrated totally into the Unconditioned. His words are precious, because they are a manifestation into speech directly from the transcendental. In a sense, you could say he was the only fully human person in the last two and a half millenia.
To the traditional Buddhist, the Buddha's words (buddhavacana) are considered flawless. As a Tathagata, all his speech is true, connected with meaning and beneficial. This is quite different from a secular view which might hold that the Buddha taught some things because of cultural conditioning or other mundane causes of error. This is a favourite tack of those who would, for instance, edit rebirth and karma out of the teachings. If the Buddha really was a Buddha, this secular line falls apart. If he could see through the most subtle levels of samsaric delusion, he wouldn't be caught by something as relatively gross as cultural conditioning.
One problem, of course, is to know if we have the real goods. If we accept that the Buddha's Word is inherently flawless, how do we know we have the real Buddha's Word? The answer is that we don't, not completely. On the other hand, scholarship reveals the sutta pitaka of the pali canon as pretty reliable as far as we can ascertain.
We can say this because of both internal and external consistency. The bulk of the suttas agree with the contents of the Chinese agamas, which have a textual tradition going back to the second council or shortly thereafter. The various recensions of the pali, in Sinhalese, Siamese and Burmese editions agree even more. This means the original texts have not been tampered with much since the traditions diverged.
Also the degree of internal consistency of the suttas is very high, much more so than the Bible for instance. We don't find instances of the Buddha saying one thing here and another contradictory thing there.
Finally, the suttas were never subject to the same degree of political manipulation as the biblical texts.
However, we cannot have the same degree of certainty about the abhidhamma. The abhidhammas of various other early schools also survive, in whole or in part, and there is nothing like the degree of agreement as between the various recensions of the sutta material. Instead, they are completely separate. It seems likely to me that the abhidhamma arose somewhat later and served, among other things, as something like a manifesto for each school clearly defining their metaphysical positions and distinguishing themselves from the others.
Nevertheless, abhidhamma can be a rewarding and useful study. It especially complements methodical vipassana meditation, and it is no accident that these are the two branches of Dhamma developed in Burma. The only caveat is that the practioneer must remain careful not to rely on word definitions at the expense of actual phenomenal experience. One of the surest ways to block spiritual progress is to convince yourself that you've already figured it out. Just because you can name something, doesn't mean you know it, even if you can name it in Pali!