Just to add yet another balancing point of view: not everyone accepts mainstream Western translations of the Buddhist canon to be faithful. For instance Stephen Batchelor (see his most recent book After Buddhism) would rather strongly disagree with attributing the "two levels" of The Two Truths to the Buddha, or the orthodox interpretation of The Four Noble Truths as being about truth statements on the nature of reality. Batchelor argues, and I would agree, that such exalted and "indescribable" depictions of nibanna are later editions to the canon for the purposes of normalising Buddhism amongst the milieu of competing spiritual worldviews. What was distinctive about what the Buddha taught, was not how he described nature, but how he advocated a practice - his legacy is verbs, not nouns.
There's a quote in the Dhammapada that I think is more clear than the "four noble truths" (which get too much emphasis):
Avoid all evil, cultivate the good, purify your mind: this sums up the teaching of the Buddhas. (183)
Matching what you said, many religions (and non-religious people) emphasize avoiding evil and cultivating good, but the practice of purifying your mind is quite good.
