I think skill challenges have two modes. (Maybe more, but I know of two.) One is essentially the "complex skill check" - to open this lock will take 4 successes, to decipher this cryptic text will take 4 successes, etc. That use of skill challenges is not (or at least need not be) metagame heavy. But it also generally won't bring out the claimed virtues of skill challenges, either - for example, if one of the PCs is weak at lock picking then s/he will just stand back and let the others go at the lock while s/he keeps watch, or shines her boots, or whatever.
For the skill challenge to achieve the virtue of engaging everyone, then the GM has to frame the situation, and adjudicate it, in a metagaming fashion - for example, s/he has to narrate consequences for checks (both successes and failures) in such a way that they suck the other PCs, and thereby the other players, into the action.